#94194: Prediabetes: An Opportunity to Prevent Diabetes

There are many tests available to assess patients suspected of having diabetes or prediabetes. These include [13]:

A diagnosis of diabetes is established when a person has any or all of the following blood glucose values [13]:

The American Diabetes Association defines persons at increased risk for diabetes (prediabetes) as those with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) and/or A1c 5.7% to 6.4%. Prediabetes should not be viewed as a clinical entity in its own right but rather as an increased risk for diabetes and cardiovascular disease.

(https://diabetesjournals.org/care/issue/47/Supplement_1 Last Accessed: January 10, 2024)

Level of Evidence: Expert Opinion

Prediabetes is an intermediate state between normal blood glucose and diabetes. The ADA specifies the following categories of increased risk for diabetes [13]:

With regard to these categories, the ADA states, "For all three tests, risk is continuous, extending below the lower limit of the range and becoming disproportionately greater at higher ends of the range" [13].

The ADA recommends testing for diabetes in asymptomatic adults who are overweight or obese and who have one or more of the following risk factors for diabetes [13]:

Patients with prediabetes (A1c ≥5.7%, IGT, or IFG) should be tested yearly. Women who were diagnosed with gestational diabetes mellitus should have lifelong testing at least every three years. For all other patients, testing for diabetes should begin at 35 years of age. If results are normal, the ADA recommends repeat testing at least every three years, with consideration for additional testing based on risk [13].

Statistics show that having prediabetes increases the risk for developing type 2 diabetes. For people with normal blood glucose, the progression to type 2 diabetes is about 5% [6]. The progression to diabetes for people with IGT is 6% to 10% per year. For persons with both IFG and IGT, the incidence of progression to type 2 diabetes is as high as 65% in six years. According to the American College of Endocrinology and the American Association of Clinical Endocrinologists (ACE/AACE), IGT should be considered a more important risk factor for progression to diabetes than IFG [6].

Approximately one-half of people with IGT meet the criteria designated for metabolic syndrome. Once known as "syndrome X," metabolic syndrome is a cluster of risk factors associated with overweight and obesity that produces insulin resistance. In patients with insulin resistance, the body produces insulin, but receptor sites on liver, muscle, and adipose tissue are ineffective. When insulin resistance is present, more insulin is needed to produce a degree of glucose-lowering effect. This results in hyperinsulinemia, meaning that there are high levels of unused insulin in the blood. Hyperinsulinemia has several adverse effects on vasculature and metabolic function.

People with metabolic syndrome have twice the risk for cardiovascular disease and five times the risk for diabetes [6]. Experts anticipate that metabolic syndrome may surpass smoking as the leading risk factor for heart disease in the near future. Because of these increased risks, it is recommended that blood lipid and blood pressure goals for persons with prediabetes should be the same as those for people with established diabetes [6].

Approximately 34% of adults in the United States have metabolic syndrome, and the incidence is increasing, which is correlated with the rise in obesity rates among adults [16]. A follow-up analysis using National Health and Nutrition Examination Survey (NHANES) data from 2011–2016 found that while the overall prevalence remained essentially the same, there was a significant increase observed among young adults 20 to 39 years of age and among the Hispanic and Asian populations [17]. In addition to excess weight and sedentary lifestyle, specific genes and increased age are also associated with metabolic syndrome and insulin resistance [18].

A person may be diagnosed with metabolic syndrome if he or she has any three of the following risk factors [16,19,20]:

The presence of metabolic syndrome is a signal of the need for lifestyle modification. Weight loss, exercise, and a low-fat diet can often improve metabolic abnormalities without medication. Even a reduction in sitting time and sedentary pastimes can have a positive effect on metabolic risk factors [21].

While the cluster of risk factors comprising metabolic syndrome has been recognized for a long time, there is mounting evidence that the individual risk factors alone are significant. "Metabolically healthy" obese men older than 50 years of age are still ten times more likely to develop type 2 diabetes than metabolically healthy men of normal weight. Some experts have concluded that the focus should be on treating the individual risk factors of metabolic syndrome rather than the cluster of abnormalities [22].

Evidence suggests that the microvascular damage from high blood glucose begins early in the progression from normal glucose tolerance to frank diabetes. Studies of people with prediabetes indicate that risk for retinopathy, nephropathy, and neuropathy are all increased [6]. Retinal microaneurysms and microalbuminuria, the hallmarks of diabetic retinopathy and nephropathy respectively, have been detected in a significant number of nondiabetic people with IGT [9]. IGT is common in patients with peripheral neuropathy, and a causal relationship has been assumed, though not adequately studied. The risk for retinopathy and nephropathy may begin to increase when two-hour postprandial blood glucose levels reach 162 mg/dL [10].

Gestational diabetes refers to diabetes that develops during pregnancy and ceases following the postpartum period. It complicates approximately 2% to 10% of all pregnancies [24]. Gestational diabetes occurs more frequently among Asian Americans, Hispanic/Latino Americans, and non-Hispanic Black Americans [25]. Other risk factors include obesity, a personal history of gestational diabetes, or a family history of diabetes. Testing for gestational diabetes should take place at the first prenatal visit if these risk factors are present. Otherwise, testing should be done between 24 and 28 weeks' gestation, usually with a glucose tolerance test [13].

Although most women with gestational diabetes will have normal glucose levels within six weeks postpartum, approximately 50% will develop type 2 diabetes in the next 10 to 20 years [24]. Therefore, regular blood glucose testing is recommended for these women during and following pregnancy. Maintenance of a healthy body weight and regular physical activity may help prevent the onset of type 2 diabetes in this population [26]. Breastfeeding in women who have had gestational diabetes is highly encouraged because it increases insulin sensitivity in the mother and can protect both mother and infant against diabetes [27].

PCOS is an endocrine disorder that affects the ovarian function of approximately 5% to 10% of women of childbearing age [28]. It is characterized by infrequent or absence of ovulation, hyperandrogenism, and/or polycystic ovaries. Signs and symptoms of PCOS include menstrual irregularities, such as amenorrhea, oligomenorrhea, or abnormal uterine bleeding. Excess androgen hormone may cause hirsutism, alopecia, and acne.

Many studies have documented an association of PCOS with insulin resistance and IGT, resulting in an increased risk for type 2 diabetes [29]. Conversion of IGT to type 2 diabetes may be 5 to 10 times more likely in patients with PCOS than in those with IGT who do not have PCOS [29]. Women with PCOS also have increased risk for cardiovascular disease.

OGTT screening for IGT is indicated upon diagnosis of PCOS and at least every two years thereafter. Because PCOS represents an independent risk factor for glucose intolerance, screening is recommended regardless of body mass index (BMI) or other additional risk factors for diabetes.

Lifestyle modification, consisting of diet, weight loss, and regular exercise, is the cornerstone of diabetes prevention in any high-risk population. There are no specific studies on prevention of diabetes in patients with PCOS. When lifestyle interventions do not achieve weight reduction, insulin-sensitizing drugs, such as metformin or a thiazolidinedione, may be considered [29].

Acanthosis nigricans is a skin condition associated with insulin resistance. Brownish-black patches, usually found on the back of the neck, in the axillae, and other areas exposed to repeated friction, characterize this condition. The slightly raised lesions of acanthosis nigricans feel velvety to the touch. Acanthosis nigricans is especially prevalent in children with type 2 diabetes and in obese dark-skinned individuals. Parents of children with this condition often mistake it for poor hygiene and attempt to treat it with vigorous scrubbing or topical applications. As a clinical indicator of insulin resistance, the presence of acanthosis nigricans should prompt screening for type 2 diabetes [13].

A study of 44,000 Black women between 30 and 69 years of age has suggested that eating out frequently is associated with an increased incidence of diabetes onset in this population [30]. The researchers found that eating restaurant meals of hamburgers, fried chicken, fried fish, and Chinese food was independently associated with an increased risk for the development of type 2 diabetes. Study participants who reported eating hamburgers twice per week had a 40% increase in risk compared to those who did not eat any restaurant meals. Eating two meals per week of fried chicken increased the risk to 68% compared to those who had none. It should be noted that greater BMI was also associated with increased risk, suggesting that the weight gain from eating these types of foods was responsible for the increased risk for developing type 2 diabetes [30].

One study examined whether maternal intake of fried foods before conception and early pregnancy was associated with gestational diabetes [31]. The researchers found that regular intake of fried fish and fried chicken was associated with an elevated risk of gestational diabetes, whereas intake of fried potatoes, chips, or donuts was not. Another study also examined the association between pre-pregnancy consumption of fried foods and risk of gestational diabetes. This prospective study included 15,027 women in the Nurses' Health Study II cohort who were followed for 10 years. During this period, the authors documented 847 incident gestational diabetes pregnancies. They found that frequent fried food consumption, particularly away from home, was significantly associated with a greater risk of gestational diabetes [32].

As noted, glucose is available to the body in two ways: from food that has been consumed and through the body's own production of glucose by the liver, a process known as gluconeogenesis. Exogenous dietary glucose is ingested via carbohydrate foods, either in the form of sugars or starches. The glucose is absorbed through the wall of the small intestine, enters the circulation, and travels to the cells throughout the body. The glucose is converted to energy after passing through the cell membrane. In order for glucose to pass through the cell membrane, insulin is required. Insulin is produced by the beta cells of the pancreas, and its role is to facilitate the entry of glucose into the cells by attaching to insulin receptors. These receptors are located primarily on the skeletal muscle and liver tissue. Normally, a rise in blood glucose after eating stimulates the production of insulin from the pancreas. Other hormones, known as incretins, also help regulate glucose homeostasis after eating.

Blood glucose that is not required for immediate energy needs may be stored in the muscle and liver tissue as glycogen. Glucagon, another pancreatic hormone, controls the release of glycogen from the liver and muscle tissue.

After eating, blood glucose rises, which stimulates the production and release of insulin from the pancreas. Incretin hormones are also released from the small intestine after the ingestion of carbohydrates, even before blood glucose levels begin to rise. Incretin hormones include glucagon-like polypeptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). These incretins affect glucose homeostasis by controlling insulin and glucagon secretion during the postprandial period. Any derangement in the normal processes of glucose metabolism can cause hyperglycemia.

An estimated 90% to 95% of people with diabetes have type 2 diabetes [33]. There are at least three major abnormalities of metabolism responsible for inducing the type 2 diabetes disease process: insulin resistance, insufficient insulin secretion, and inappropriate glucose production.

Insulin resistance, or the impairment of the body to effectively utilize available insulin, is the hallmark of both metabolic syndrome and type 2 diabetes. In people with early stage type 2 diabetes, insulin resistance reduces glucose uptake by 35% to 40%. With insulin resistance, the pancreas may produce normal or greater than normal amounts of insulin, but receptor sites for it are not available. For some people, the pancreas is temporarily able to make enough additional insulin to overcome the insulin resistance and produce normal blood glucose levels. Hyperinsulinemia is usually the case in early stages of type 2 diabetes and is associated with macrovascular risk factors of the metabolic syndrome, such as dyslipidemia and hypertension. High levels of insulin in the blood increase sympathetic activity that can raise blood pressure.

Insufficient insulin secretion by the pancreas usually occurs as part of the natural history of insulin resistance. When insulin resistance is prolonged, pancreatic beta cells ultimately become fatigued due to the hyperactivity required to compensate for persistent elevated blood glucose. Eventually, the beta cells can no longer produce enough insulin to meet the body's needs, and mild hyperglycemia begins to develop. Because the role of insulin is to facilitate the passage of glucose into cells, blood glucose continues to rise. Unfortunately, mild hyperglycemia is rarely symptomatic, and many people miss the opportunity to intervene with lifestyle changes that can prevent progression to type 2 diabetes at this point.

Inappropriate glucose production by the liver is a third major metabolic abnormality in diabetes. As an organ that can make or store glycogen, the liver plays a major role in regulation of blood glucose levels. In normal physiology, the liver can store glycogen and release it as needed to keep blood glucose in a normal range. In type 2 diabetes, insulin resistance of receptor sites can prevent the liver from receiving the signals it needs to stop releasing glucose when blood levels are sufficient. When this occurs, glucose output from the liver increases, causing blood glucose to continue rising inappropriately.

The presence of adipose tissue plays a role in glucose metabolism and the development of metabolic syndrome. In the past, adipose tissue was generally regarded as an inert substance that was related in some way to diabetes and cardiovascular disease. Today, fat tissue is recognized as a metabolically active organ, secreting hormones, cytokines, and enzymes that can affect functions throughout the body. In fact, fat is considered an endocrine organ.

Excessive fat cells contribute to insulin resistance. As fat cells enlarge, they become hypoxic, interfering with insulin uptake and causing collagen and fiber around the cells to increase. The resulting insulin resistance not only contributes to the development of hyperglycemia, but hypertension as well. Hepatic fat, which can lead to non-alcoholic liver disease, is more strongly related to insulin resistance than visceral fat.

The chronic complications of diabetes have an immense effect on the healthcare system, society, and the individual. While the economic costs of diabetic complications are enormous, their affect upon quality of life for the individual and family can be equally devastating. The CDC reports the impact of chronic complications upon Americans with diabetes as [3]:

The chronic complications of diabetes are usually classified as microvascular or macrovascular according to the type of blood vessel damage that underlies the problem. Microvascular complications of diabetes include retinopathy, nephropathy, and neuropathy. Prolonged hyperglycemia leads to changes in the structure of the microscopic vessels that supply the eye, the kidney, and the nerves.

Macrovascular complications of diabetes are coronary artery disease, cerebral artery disease, and peripheral vascular disease. Heart disease is the foremost cause of death in people with diabetes [3]. Moreover, people with diabetes are prone to developing both coronary and cerebral vascular disease at an earlier age than people who do not have diabetes.

Much research over the past two decades has demonstrated that good glycemic control can prevent the onset and slow the progression of the chronic complications of diabetes. Maintaining an A1c of 7% to 6.5% or less is recommended for most people with diabetes for the prevention of complications [13]. Furthermore, blood pressure control, healthy lipid levels, and freedom from tobacco use offer additional significant reductions in risk.

Treatments for type 2 diabetes include moderation of carbohydrate intake, weight management, exercise, medication, and stress management. Most people with diabetes perform self-monitoring of blood glucose (SMBG) on a regular basis. Diabetes management requires substantial and ongoing self-care activity on the part of the patient or caregiver. Self-management education is a hallmark of diabetes treatment and is associated with improved outcomes. These same steps should be taken in patients with prediabetes to prevent progression of the disease and sequelae.

The DPP was a multicenter study involving 3,234 subjects with prediabetes, all whom were overweight. The subjects were assigned to one of three groups:

At the end of nearly three years, the lowest incidence for developing type 2 diabetes was in the lifestyle intervention group. This demonstrates that weight loss and increased physical activity are more significant factors in diabetes prevention than the use of medication or placebo. For each study group, the approximate incidence of developing diabetes in three years was:

These results indicate that millions of people at risk for type 2 diabetes could delay or prevent the disease by losing approximately 7% of their body weight through increasing exercise and eating a diet low in fat and calories. Overall, people in the lifestyle intervention group were able to reduce their risk for type 2 diabetes by 58%. After 10 years, the lifestyle group still had a 34% reduction in risk as compared to the placebo group. Reduction in risk was true for all participating ethnic groups and without regard to gender. Lifestyle modification was shown to be particularly beneficial to participants 60 years of age and older, whose risk was reduced by 71% [34,35].

Further analyses of DPP data have concluded that changes in diet and exercise leading to weight loss have significant benefits in addition to diabetes prevention, including [35]:

The results of the DPP also showed that diabetes could be prevented with the use of metformin in people with prediabetes, with risk reduction of about 31% [35]. Risk reduction with use of metformin was found to be most effective for people 25 to 44 years of age and in those who had a body mass index of 35 or higher [35]. After 10 years, the incidence of type 2 diabetes was decreased by 18% in the metformin group as compared to placebo [34].

Another study, Action for Health in Diabetes (Look AHEAD), supports the findings of the DPP, showing that intensive lifestyle intervention designed to achieve and maintain weight loss produces improvements in glycemic control, as well as other health benefits. Look AHEAD is a large, 13-year study of cardiovascular morbidity and mortality in overweight or obese people with type 2 diabetes. At the four-year point, it has been found that lifestyle modifications similar to DPP recommendations can result in weight loss, reduction in blood pressure and improved lipid profile, in addition to improvement in blood glucose levels [36]. Other studies, such as the Da Qing IGT and Diabetes Study and the Finnish Diabetes Prevention Study, also provide strong evidence for the benefit of lifestyle modification in the prevention of diabetes [37].

Based on the results of several major research studies, including the DPP, the ACE/AACE make the following statement in support of preventing type 2 diabetes [6]:

The American Diabetes Association asserts that patients with prediabetes should be referred to an intensive behavioral lifestyle intervention program modeled on the Diabetes Prevention Program to achieve and maintain 7% loss of initial body weight and increase moderate-intensity physical activity (e.g., brisk walking) to at least 150 minutes per week.

(https://diabetesjournals.org/care/issue/47/Supplement_1 Last Accessed: January 10, 2024)

Level of Evidence: A (Clear evidence from well-conducted, generalizable randomized controlled trials that are adequately powered)

Individuals with prediabetes should be referred to an intensive behavioral lifestyle intervention program that is modeled on the DPP and/or to individualized medical nutrition therapy provided by a registered dietitian knowledgeable about diabetes care [38]. Lifestyle recommendations for people with prediabetes include [6,13,38]:

Lifestyle modification is recommended for all ages, although individual adjustment may be made based on a specific patient's needs. Studies have indicated that education on lifestyle modification to prevent diabetes can be effective in either individual or group formats [6,39].

The Mediterranean diet is based on the dietary traditions of Crete, Greece, and Southern Italy as they were practiced in the 1950s and 1960s. This was a time when the rates of chronic disease in that area were among the lowest in the world and adult life expectancy was the highest, despite the fact that medical services were limited. Ironically, it was considered a diet of the "poor" at the time, because it included small amounts of beef and processed foods, which were then valued as dietary symbols of prosperity. This traditional diet was plant-based, consisting mainly of fruits and vegetables, beans, nuts, whole grains, and fish, with moderate consumption of olive oil and red wine. It included relatively small amounts of dairy and red meat.

According to the American Diabetes Association, nutrition counseling for weight loss, including a reduction of total dietary fat and calories, is recommended for patients with prediabetes. However, evidence suggests that there is not an ideal percentage of calories from carbohydrate, protein, and fat for all people to prevent diabetes; therefore, macronutrient distribution should be based on an individualized assessment of current eating patterns, preferences, and metabolic goals.

(https://diabetesjournals.org/care/issue/47/Supplement_1 Last Accessed: January 10, 2024)

Strength of Recommendation/Level of Evidence: B (There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial.)

Scientists have studied the Mediterranean diet intensely over the past 50 years, resulting in ample evidence that the diet is associated with health benefits. Several of these studies have concluded that a Mediterranean-type diet can help prevent diabetes, assist in weight loss, prevent overweight people from progressing to obesity, lower the risk for heart disease, and decrease the need for medication in diabetic patients [42,43,44]. A 2009 study on the effects of the Mediterranean diet on postprandial blood glucose and lipid levels of people with type 2 diabetes has led researchers to conclude that "this kind of diet…could be considered a first line of choice for the treatment of patients with type 2 diabetes" [43]. One study of the long-term effects (8.1 years follow-up) of a Mediterranean-style diet found that it resulted in a greater reduction of A1c levels, higher rate of diabetes remission, and delayed need for diabetes medication in patients with newly diagnosed type 2 diabetes [45].

General tenets of the Mediterranean-type diet include [42]:

Dietary Approaches to Stop Hypertension (DASH) is an evidence-based eating plan that has been shown to lower blood pressure in people with moderate-level hypertension, without the use of antihypertensive medication. Adhering to DASH can also result in reduced doses of medication in people with more severe hypertension [46]. This eating plan is recommended by the National Heart, Lung, and Blood Institutes and the American Heart Association and is included as an example of a healthy eating plan in the U.S. Department of Agriculture Dietary Guidelines for Americans [41]. Research has found that following the DASH eating plan can also offer protection against the development of type 2 diabetes [45,47,48].

The DASH eating plan emphasizes fruits, vegetables, low-fat dairy foods, whole grains, and one serving of nuts, seeds, or legumes per day. This results in increased consumption of potassium, calcium, magnesium, and fiber, nutrients that are associated with blood pressure reduction. The plan also includes moderate amounts of protein, low consumption of total fat, and decreased intake of sodium. The U.S. Department of Health and Human Services (USDHHS) has published a consumer guide that includes detailed information on how to follow the DASH guidelines, including meal plans and recipes [46]. Although not a weight-loss plan per se, evidence suggests that people can lose weight while following the DASH guidelines along with increasing physical activity. Patients can be referred to the USDHHS booklet on DASH for guidelines on lowering calories while following the DASH eating plan [46].

Weight loss is a primary goal of prediabetes management [49]. Overweight people have a higher risk for prediabetes, diabetes, heart disease, and a number of other serious health problems. For people with diabetes and prediabetes, moderate weight loss (5% to 7% of body weight) can improve insulin action and decrease fasting blood glucose [50]. Moderate weight loss can also lower the risk for cardiovascular morbidity, associated with diabetes and prediabetes, by decreasing blood pressure and improving the lipid panel.

Reducing calories and increasing physical activity are the cornerstones of healthy weight loss [51]. Successful weight management to improve overall health requires a lifelong commitment to a healthful lifestyle that emphasizes sustainable and enjoyable eating practices and daily physical activity [49,51]. For safe weight loss, the Academy of Nutrition and Dietetics and the ADA recommend a reduction of 500 to 1,000 calories per day to achieve a target weight-loss rate of 1 to 2 pounds per week [51].

A pivotal finding from the DPP was that diabetes could be prevented with only modest weight loss in at-risk subjects. It is notable that the weight loss target for the lifestyle intervention group was 7% of initial body weight, not attainment of ideal body weight. The actual results showed that even 5% weight loss was significant for disease prevention. For nurses and other healthcare providers, these results justify education and counseling to support modest weight loss in overweight patients. Suggesting a smaller, more achievable initial weight-loss target can help patients who feel overwhelmed by the expectation that they must lose a great deal of weight to achieve health benefits. To suggest an initial short-term weight loss goal of 5% might be a more realistic first step that is more likely to encourage and motivate patients.

A reduced-calorie diet is the basis for healthy weight loss. As stated, the Academy of Nutrition and Dietetics recommends a reduction of 500–1,000 calories per day, with a target weight loss of 1 to 2 pounds of weight loss per week [51]. Counseling patients on safe and effective weight loss and healthy eating includes many strategies.

Effective weight management should include assessment and intervention by a multidisciplinary team, including a physician, registered dietitian, exercise physiologist, and behavior therapist [51]. While the interdisciplinary team approach is considered the "gold standard," access to these professionals is not always feasible for patients whose healthcare plans do not cover all of these services or for those who live in remote geographic areas. In these cases, a nurse or other knowledgeable healthcare provider may assume responsibility for teaching weight reduction and healthy eating by utilizing recommendations and evidence-based practice standards from these other disciplines. Research evidence supports that a relatively inexpensive program involving nurse support is as effective as a more resource-intense program for weight maintenance over a two-year period [59].

The following information is not intended, nor is it able, to replace the specialized training and knowledge of a registered dietitian or other specialists in weight management. However, because these resources are not always available, the information provided here can serve as a guide to nutrition education for the prevention of diabetes.

Portion Control

The term "portion distortion" refers to the perception that the amount of food served on a plate or at any single eating occasion is the appropriate amount to eat, no matter the size. It has been shown that people who eat too much at one time do not compensate by eating less later in the day. Furthermore, larger portion sizes override hunger and satiety signals, so eating continues beyond the feeling of fullness [21,51]. Portion distortion is reinforced in society by restaurants that serve large helpings, food sold in large packages, and larger size plates and eating utensils.

Studies indicate that portion control is a valid component of a healthy and effective weight loss plan. Based on these studies, the Academy of Nutrition and Dietetics recommends that portion control be integrated into the weight-loss plan. To help patients with portion control, advise them to [61]:

• Read Nutrition Facts labels to identify appropriate serving sizes.

• Eat from a plate, not a package. Avoid eating directly out of a bag or bowl. Put one serving on a plate or dish.

• Try portioning out foods with measuring cups and spoons to get an idea of what the serving size looks like (Table 1). Compare these serving sizes to the sizes of everyday objects (Table 2).

• Use smaller plates, bowls, and utensils for eating.

• Be aware of large serving sizes in restaurants. Place half of a large portion in a take-home container before starting the meal or share an entree with another person.

• Practice the "plate method" of portion control.

GUIDE TO SERVING SIZES FOR MEAL PLANNING

Category	One Serving Size
Bread	1/4 large bagel (1 oz.) 1 biscuit (2.5 inches across) 2 slices (1.5 oz., reduced-calorie, light) 1/2 English muffin 1/2 hot dog or hamburger bun 1 4-inch pancake 1/2 of 6-inch pita 1 6-inch corn tortilla 1 4-inch waffle square
Cereals and grains (including pasta and rice)a	1/3 cup barley, couscous, pasta, quinoa, rice (white, brown, other types and colors) 1/2 cup bulgur, tabbouleh, wild rice 1/2 cup bran cereal or shredded wheat 1/4 cup granola 1/2 cup hot cereal (oats, oatmeal, grits) 3/4 cup unsweetened ready-to-eat cereal
Starchy/non-starchy vegetables	1/2 cup cooked corn, green peas, mixed vegetables, parsnips 1/2 cup marinara or spaghetti sauce 1/4 large (3 oz.) baked potato, with skin 1 cup (2 oz.) French-fried (oven-baked, skin on) potato 1/2 cup mashed potato (with milk and fat) 1 cup winter squash 1/2 cup yam or sweet potato 1/2 cup cooked vegetables 1 cup raw vegetables 1/2 cup vegetable juice
Fruits	1/2 cup unsweetened applesauce 1 extra-small banana 3/4 cup blueberries 2 Tbsp dried fruits 1/2 cup canned fruit 1 small fruit (e.g., whole apple) 1/2 cup unsweetened fruit juice 17 small grapes (3 oz.) 1 cup diced melon 1 1/4 cups whole strawberries
Milk and milk substitutes	1 cup milk (nonfat, 1%, 2%, whole) 2/3 cup plain or sweetened yogurt 1 cup rice drink, plain, fat-free
Meat and other proteins	1 oz fish, chicken, or beef (cooked) 1/4 cup cottage cheese 1 egg 1 Tbsp peanut butter 1/2 cup tofu
Fats and oils	1 tsp oil 1 tsp butter or margarine 2 Tbsp avocado 1 Tbsp regular salad dressing 1 tsp regular mayonnaise 1 Tbsp light mayonnaise
Sweets and desserts	1/2 cup ice cream 1 1/4-inch square brownie, unfrosted 2 small cookies 3 pieces hard candy 1/2 cup sugar-free pudding 2-inch square unfrosted cake
aServing sizes for grains and pasta measure cooked foods.

Table 1

Source: [62]

SERVING SIZES AS COMPARED TO COMMON OBJECTS

Serving Size	Is The Same Size As
Grain Products
1 pancake	CD or DVD
1/2 cup cooked, rice, or pasta	1/2 baseball
1 cup cereal flakes	Fist
1 slice bread	Cassette tape
1 piece cornbread	Bar of soap
Meat/Fish/Poultry/Protein
3 oz. meat, fish, and poultry	Deck of cards
3 oz. grilled/baked fish	Checkbook
2 Tbsp. peanut butter	Ping pong ball
Vegetables/Fruit
1 cup salad greens	1 baseball
1 baked potato	Fist
1 med. fruit	1 baseball
1/2 cup fresh fruit	1/2 baseball
1/4 cup raisins	1 large egg
Fats
1 tsp. margarine or spreads	1 die or the tip of your thumb
Dairy/Cheese
1.5 oz cheese	4 stacked dice or 2 cheese slices
1/2 cup ice cream	1/2 baseball

Table 2

Source: [63]

The Plate Method

A group of dietitians in Idaho developed the Idaho Plate Method in 1993, based upon an earlier model from Sweden[64]. Since its inception, the plate method has been widely utilized in health education as a practical and effective way of teaching healthy eating behavior[41,65,66,67]. Its premise is that healthy eating and controlling portion sizes can be simplified by using a visual image. While incorporating the nutritional recommendations from the ADA, the plate method helps people with diabetes lose weight, reduce the incidence of hypoglycemia, and make better food choices[41,66]. Information regarding the Idaho Plate Method may be accessed online at http://www.platemethod.com.

This method has since been modified specifically for patients with diabetes. The Diabetes Plate Method is a useful visual to assist in portioning meals without measuring (Figure 1). The teaching tenets of the Diabetes Plate Method are [64,65]:

• Use a nine-inch plate.

• Fill approximately half the plate with non-starchy vegetables, such as leafy greens, onions, peppers, tomatoes, cucumbers, green beans, broccoli, carrots, cauliflower, or mushrooms.

• Fill one-fourth of the plate with protein foods, such as lean cuts of meat, fish, poultry without the skin, tofu, one to two eggs, 2 ounces of low-fat cheese, one-third cup nuts, or 2 tablespoons of peanut butter.

• Fill one-fourth of the plate with carbohydrates, such as whole-grain bread, brown rice, whole-grain pasta, potato, beans, lentils, corn, peas, fruit, dried fruit, or yogurt. This section may also be replaced with a glass of milk.

• Choose water or a low-calorie drink, such as unsweetened tea or coffee, sparkling water, or diet drinks.

THE PLATE METHOD

Figure 1

Source: [64,65]

The plate method is very helpful as a first step in learning to control portion sizes and to choose healthy foods in the right amounts. It is useful for patients who are busy or overwhelmed by too much information and for those who do not like strict regimens. People of low-literacy and those who have barriers to weighing and measuring foods may find the plate method the most acceptable approach to healthy eating and weight management [64,65].

MyPlate

In 2011, the USDA Center for Nutrition Policy and Promotion released the 2010 Dietary Guidelines for Americans, which place greater emphasis on promoting the consumption of nutrient-dense foods and to achieving and maintaining a healthy weight. These guidelines were updated in 2020 and now recommend personalizing an individual's food plan based on age, sex, height, weight, and physical activity level. Information about the MyPlate Plan is available athttps://www.myplate.gov [41,68].

The MyPlate Plan illustrates a plate being one-half filled with vegetables and fruits (Figure 2). By comparison, the Plate Method shows one-half of the plate filled with vegetables only and fruit included in the carbohydrate section. Both plates display one-fourth filled with lean protein[65]. The MyPlate Plan also includes one-fourth of the plate filled with grains, of which at least one-half should be whole grains. In addition, a serving of low-fat or fat-free dairy milk or yogurt (or lactose-free dairy or fortified soy version) may be added. All foods and beverages should contain limited amounts of added sugars, saturated fat, and sodium[41].

THE MYPLATE PLAN

Figure 2

Source: [68]

Label Reading

Knowing how to read the Nutrition Facts labels (Figure 3) can help patients make informed food decisions to choose a healthy diet and help with weight management and diabetes prevention[72,73,74]. A 2016 redesign of the Nutrition Facts label includes larger, bolder type for the number of servings; updated serving sizes; calories listed in larger type; updated Daily Values (and a footnote explaining them); a new fact indicating "added sugars;" and a change to the nutrients required section, with amounts (in percentages) declared[75].

SAMPLE NUTRITION FACTS LABEL

Figure 3

Source: [75]

Instruct patients to consider the following when reading Nutrition Facts labels [74,76]:

• Check the serving size (the amount typically eaten at one time) and the number of servings per package. Compare your individualized portion size to the serving size. If the label indicates a serving size of one cup and you eat two, you are consuming twice the calories, fat, and other nutrients than that listed on the label.

• Note the number of calories in a single serving. Compare calories and fat grams per serving among different products and choose foods that are lower in fat and calorie content per serving. Understand nutrition terms (Table 3).

• Let percent of Daily Values be a guide to assess how a particular food fits into your daily meal plan. A Daily Value of 5% or less is low; 20% or more is high. Percent of Daily Values is for an entire day, not just one meal or snack, and are average levels of nutrients for someone consuming 2,000 calories/day, which may be more or less than you need.

• Choose foods that are low percentage Daily Values in saturated fat, "added sugars," and sodium to reduce your risk of chronic disease. The recommended daily intake of sodium is 2,300–2,400 mg or less (with 2,000 mg or less often recommended for people with certain cardiac conditions). Aim for entrees with less than 600 mg sodium per serving, side dishes with less than 400 mg, and snacks with a maximum of 200 mg of sodium per serving.

• Avoid foods that list trans fat on the label. Trans fats originate from the process of hydrogenating oil. The goal is to consume zero trans fats.

• Aim for foods with high percentage Daily Values of fiber, potassium, vitamin D, calcium, and iron, and include foods with more of these nutrients in your daily meal plan.

• Understand the additional nutrients (e.g., protein, carbohydrates, sugars). Eat these foods in moderation. A daily percentage Daily Values for protein is not required on the label. Carbohydrates include sugars, starches, and fiber. Fiber is beneficial for weight loss and blood glucose control. A product is considered a good source of fiber if it has 2.5–4.9 g fiber/serving. Foods can officially be labeled "high fiber" if they contain at least 5 g fiber/serving. Whole-grain breads, grains, and rice are the healthiest choice. Total sugars includes those naturally present in many nutritious foods and beverages (e.g., milk, fruit)."Added sugars" are added during the processing of foods. Avoid foods containing high amounts of added sugars.

• Ingredients are listed in order from most to least. Highly processed foods usually have a long list of ingredients; healthier choices often have shorter ingredient lists.

UNDERSTANDING NUTRITION TERMS

Term	Definition
Low calorie	40 calories or less per serving
Low cholesterol	20 mg or less and 2 g or less of saturated fat per serving
Reduced	At least 25% less of specified nutrient or calories than the usual product
Good source of	Provides at least 10% to 19% of DV of a particular vitamin or nutrient per serving
Excellent source of…	Provides at least 20% or more of DV of a particular vitamin or nutrient per serving
Calorie free	Less than 5 calories per serving
Fat free/sugar free	Less than 1/2 g fat or sugar per serving
Low sodium	140 mg or less of sodium per serving
High in	Provides 20% or more of DV of a specified nutrient per serving

Table 3

Source: [76]

The U.S. Food and Drug Administration (FDA) provides a sample Nutrition Facts label that can be used to check a patient's label-reading skills [77].

While the FDA regulates food label claims, consumers should be aware of marketing ploys that can be misleading. Many packaged foods make health statements such as "light" and "all natural," but some of these claims and terms are not approved by the FDA. For example, claims such as "all natural," "doctor-recommended," and "strengthens your immune system" are not FDA approved.

As stated, people eat for a variety of reasons. The quantities, proportions, and variety or combination of foods, drinks, and nutrients in individual diets and the frequency with which they are consumed constitute dietary patterns. According to the 2020–2025 Dietary Guidelines for Americans, the dietary patterns that are associated with beneficial outcomes for all-cause mortality, overweight/obesity, and type 2 diabetes include higher intakes of fruits and vegetables, legumes, whole grains, low- or non-fat dairy, lean meat and poultry, seafood, nuts, and unsaturated vegetable oils [60]. Plant-based diets (i.e., eating patterns that avoid the consumption of most or all animal products and support a high consumption of fruits, vegetables, legumes, seeds, whole grains, and nuts) have been shown to significantly and positively impact the management of diabetes [81].

The U.S. Preventive Services Task Force (USPSTF) analyzed four types of weight-loss interventions: behavior-based weight loss (80 trials); behavior-based weight loss maintenance (9 trials); pharmacotherapy-based weight loss (32 trials), and pharmacotherapy-based weight loss maintenance (3 trials) [84]. The Task Force found moderate evidence supporting intensive, multicomponent behavioral interventions in obese adults. Such interventions can lead to clinically significant improvements in weight status and can reduce the incidence of type 2 diabetes. The USPSTF recommends that adults with a BMI of 30 or higher be referred to intensive, multi-component behavioral interventions for weight loss support and maintenance [84].

The research reviewed by the 2020 Dietary Guidelines Advisory Committee supports a lifespan approach to nutrition, beginning in the earliest stages of life and continuing into adulthood [60]. A lifespan approach reinforces the importance of implementing dietary patterns (from birth to adulthood) that are most associated with adequate nutrition for every life stage. Each life stage provides individuals (or their parents) with the opportunity to make food choices that promote health and well-being, achieve and maintain appropriate weight, and reduce the risk of diet-related chronic disease. A dietary patterns approach also allows for accommodations for cultural, personal, and individual needs and food choice preferences [41,60].

As discussed, food and eating serve many purposes and have multiple meanings for people. For example, eating can provide socialization, emotional comfort, and relief from stress and anxiety. Eating also can be driven by environmental cues and other external forces.

Behaviors associated with overweight and obesity include excessive television watching, decreased physical activity, frequent eating at fast food restaurants, consuming foods high in fat and sugar, skipping breakfast, and lack of portion control. Effective weight loss counseling includes exploring the behavioral components of a patient's dietary habits and assisting with problem solving. Mindful eating is a valuable skill that can result in healthier lifestyle habits. The food diary and the hunger scale are useful tools for increasing awareness of one's actual physical need for food and for monitoring the quantity of food consumed.

Nutritional counseling should provide help in understanding reasons for "emotional eating." This includes helping patients identify feelings related to eating and determining where the feelings originate. It may involve encouraging the patient to respond to feelings in ways other than eating. For example, if the patient identifies that he or she is bored, explore other enjoyable activities that could be done instead of eating. If a patient is depressed, provide sources of support for that problem. Thorough assessment may reveal the need for a mental health referral for help with emotionally rooted eating behaviors.

The Association of Diabetes Educators (AADE) recommends asking patients the following questions to help with problems related to eating behavior [85]:

What three words fill in the blanks for you? When I think about healthy eating, I feel ______, _____, and _____. This question helps examine the emotions the patient has about eating and that he or she may have toward making behavior changes. If this exploration reveals barriers, it is best to ask the patient first what he or she believes will help to overcome it. The next step is to offer suggestions to enhance the patient's own ideas, if indicated.

What did you eat for dinner last night? Is there anything you could have done to make your meal healthier? These questions help assess patients' food preferences and increase their awareness of what they are eating. By asking patients to generate their own ideas for improvement, they are empowered to make behavior changes on their own behalf.

For you, what is the hardest part about healthy eating? This question enables patients to identify challenging situations and to solve problems. Healthcare professionals can guide them in making their own plan to avoid the identified problems or to be prepared to make better choices when an unavoidable situation arises.

What is the best part about healthy eating? When patients make their own statement about how change will be beneficial, it facilitates readiness. This is a powerful component of motivational interviewing, which is discussed more thoroughly in a later section of this course.

A step-wise approach to behavioral problem solving also can be helpful. Kaiser Permanente Health Education Services recommends the following sequence for behavioral problem solving [86]:

While there are no specific recommendations for evaluating the person with prediabetes for exercise clearance, guidelines do exist for people with diabetes and other chronic conditions. The ADA recommends that people with diabetes should be assessed before beginning a program of physical activity if it is going to be more vigorous than brisk walking. This assessment should include looking for conditions that may be associated with increased likelihood of cardiovascular disease. However, the circumstances under which a graded electrocardiogram (EKG) stress test should be considered are not well defined. Cost analysis studies have indicated that the widespread use of this test is cost-prohibitive, partly due to high risk of false-positive results, which trigger subsequent invasive testing procedures. The recommendation is that medical providers weigh the potential benefits of this type of testing against risks and costs in each individual case.

Pre-exercise medical clearance is not necessary for asymptomatic individuals receiving diabetes care consistent with guidelines who wish to begin low- or moderate-intensity physical activity not exceeding the demands of brisk walking or everyday living. Individuals who plan to increase their exercise intensity or who meet certain higher-risk criteria may benefit from referral to a healthcare provider for a checkup and possible exercise stress test before starting such activities [88].

Studies indicate that most people with type 2 diabetes show decreases in blood glucose after mild-to-moderate exercise [89]. The magnitude of glucose lowering is proportionate to the duration and intensity of the exercise and persists into the post-exercise period, prolonging its benefits over two to three days [89]. Another noteworthy benefit of regular exercise is the reduction of risk factors for cardiovascular disease, such as hypertension, insulin resistance, and dyslipidemia.

Exercise improves carbohydrate metabolism and insulin sensitivity. It reduces blood glucose by lessening the production of glucose by the liver and by increasing blood glucose utilization by the skeletal muscle. Improvement in insulin sensitivity from a single bout of exercise lasts 24 to 72 hours, depending on the duration and intensity of the exercise [89]. Exercises that increase muscle mass, such as resistance exercises, can lead to enhanced glucose metabolism, as greater muscle mass is associated with better insulin uptake.

Besides lowering blood glucose, improvement in insulin sensitivity also mediates the negative effects of metabolic syndrome, reducing such cardiovascular risk factors as hypertension, hyperinsulinemia, central obesity, lipid disorders, and inflammatory markers such as C-reactive protein [89]. Other health benefits related to regular physical activity include reduced risk for osteoporosis, obesity, colon cancer, breast cancer, peripheral vascular disease, anxiety, and depression. For older adults, regular exercise is also associated with a reduced risk of falls and injury [89].

Successful weight loss and long-term maintenance of lost weight require a combination of healthy nutrition, regular exercise, and behavior modification. Research shows that weight loss is more likely to occur as a result of decreased calories in the diet than from calorie burning during exercise. This is because it is very difficult for most people to create the 500 to 1,000 calorie per day deficit needed for weight loss with exercise alone [51].

The benefit of exercise to weight loss is considered "dose related," meaning that greater weight loss and less weight regain are associated with increased amounts of exercise. Moderate-intensity physical activity for between 150 and 200 minutes per week is effective in preventing weight gain, but it will not result in clinically significant weight loss without calorie restriction. Amounts of moderate-intensity physical activity beyond the recommended 150 minutes per week are usually necessary to bring about significant weight loss in the absence of calorie restriction. According to the ACSM, 200 to 300 minutes of exercise per week will provide modest weight loss. Specifically, 225 to 420 minutes (approximately four to seven hours) of moderate exercise per week are associated with weight loss of roughly 11 to 16 pounds over several weeks [90].

Although evidence suggests that 150 minutes of exercise per week alone does not result in significant weight loss, the DPP concluded that this amount does prevent diabetes, most likely by increasing insulin sensitivity. Exercise is also a critical element in preventing weight regain after the initial loss. Furthermore, it reduces risk for cardiovascular disease and diabetes beyond that produced by weight loss alone. Therefore, exercise prevails as an essential component of a healthy lifestyle for promoting overall weight loss, weight maintenance, and chronic disease prevention [51].

It is important to guide patients to select a specific exercise plan that meets their abilities and personal preferences. Too often, patients are simply told to "get some exercise" without any support in selecting a specific and appropriate plan. Developing a plan consists of specific recommendations regarding how much activity to engage in, what type of activity, and how and when it will take place. Things to take into account include the patient's individual lifestyle, cultural preferences, current fitness level, physical limitations, social situation, schedule and time commitments, and personal preferences. It may be helpful to begin by asking patients what they are already doing or might like to start doing. This helps identify what they are most motivated to do.

It is also important to help patients select a program that will have the greatest chance for long-term maintenance. The ACSM has identified factors that influence maintenance of exercise behavior [89]:

Encourage patients to choose activities that are realistic for them. Walking is the preferred form of exercise for most obese patients, but others may prefer swimming or exercise classes. Attainable goals allow patients to experience success and potentially increase morale. Modest initial goals allow for gradual increase in duration and frequency of activity.

One arm of the DPP research study examined the efficacy of metformin as a pharmacologic agent to prevent the onset of type 2 diabetes in high-risk people. Results indicated that metformin reduced diabetes onset by 31%, whereas lifestyle intervention reduced the risk for diabetes onset by 58% [2]. Metformin was found to be most effective in younger, more obese patients and showed little benefit for those 60 to 85 years of age [2]. Reviews of more than two decades of clinical use have demonstrated that metformin is generally well-tolerated and safe and beneficial for diabetes prevention among higher-risk patients [101,102]. It also may be beneficial for patients who are unable to adhere to lifestyle changes [103].

Long-term use of metformin therapy has been associated with vitamin B12 deficiency. The ADA recommends periodic B12 measurement in patients treated with metformin, particularly those with anemia or peripheral neuropathy [13].

In addition to lifestyle measures, the American Diabetes Association recommends metformin therapy for prevention of type 2 diabetes should be considered in those with prediabetes, especially those 25 to 59 years of age with BMI ≥35, higher fasting plasma glucose (e.g., ≥110 mg/dL), and higher A1c (e.g., ≥6.0%), and in individuals with prior gestational diabetes mellitus.

(https://diabetesjournals.org/care/issue/47/Supplement_1 Last Accessed: January 10, 2024)

Level of Evidence: A (Clear evidence from well-conducted, generalizable randomized controlled trials that are adequately powered)

As of 2023, no drug is approved by the FDA to prevent diabetes or treat insulin resistance. However, the ADA recommends that metformin therapy be considered for the prevention of diabetes in certain patients, including [13]:

Other antidiabetic medicines have also been studied for their effect on diabetes prevention. Rosiglitazone is an insulin-sensitizing drug that has led to reduced incidence of diabetes in clinical trials, but its long-term effectiveness is not known. Furthermore, clinical trials have not compared the effectiveness of rosiglitazone to lifestyle intervention or other pharmacologic agents. Other evidence suggests that using low-dose combination therapy of metformin and rosiglitazone results in risk reduction for diabetes onset [104]. In July 2010, the FDA reviewed the safety of rosiglitazone based on its potential for cardiovascular side effects. The advisory committee determined that rosiglitazone could remain on the market but with restrictions on its use and additional warnings about the risk for myocardial infarction and congestive heart failure [105]. These restrictions were removed in November 2013 after the FDA determined that data did not demonstrate an increased risk of heart attack with rosiglitazone compared with the standard type 2 diabetes medications metformin and sulfonylurea [106]. Risk Evaluation and Mitigation Strategy (REMS) is a drug safety program the FDA can require for medications with serious safety concerns. In December 2015, the FDA eliminated the REMS for rosiglitazone after a period of continuous monitoring revealed no new pertinent safety issues [107]. Other reported side effects of rosiglitazone include weight gain, bone fracture, and peripheral edema (rare) [105].

The Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication (DREAM) trial reported that three years of therapy with rosiglitazone reduced the primary outcome of diabetes or death by 60% [108]. A passive follow-up study (DREAM On) investigated whether diabetes prevention persisted more than 1.5 years after discontinuation of therapy [108]. Consenting participants had repeat OGTT one to two years after therapy ended. A diagnosis of diabetes was based on either a fasting glucose level of ≥7.0 mmol/L, or a two-hour plasma glucose level of ≥11.1 mmol/L), or a confirmed diagnosis by a physician not involved in the study. Regression to normal blood glucose was defined as a fasting glucose level of <6.1 mmol/L or a 2-hour plasma glucose level of <7.8 mmol/L. After a median of 1.6 years post-trial, the rosiglitazone participants had a 39% lower incidence of diabetes or death and 17% more regression to normal blood glucose. Similar incidences of the primary outcome and regression were observed in participants from both the ramipril and rosiglitazone groups. Ramipril did not have any significant long-term effect. Rosiglitazone reduced the longer term incidence of diabetes by delaying, but not reversing, the underlying disease process [108].

Another drug, acarbose, was found to reduce the progression of IGT to type 2 diabetes by 25% over 3.3 years in one study [109]. Because this medication can cause significant gastrointestinal side effects, many subjects discontinued the study medication [105]. This raises questions about the efficacy and practicality of using acarbose to prevent type 2 diabetes in actual clinical practice [109].

A review of eight randomized controlled trials investigated the effects of acarbose in people with IGT, IFG, moderately elevated A1c, or any combination of these [110]. Trial duration ranged from one to six years, and most trials compared acarbose with placebo. Of 4,014 participants who received acarbose, 670 (16.7%) developed diabetes; of 3,994 participants who received placebo, 812 (20.3%) developed diabetes. When acarbose was compared with no intervention, 7 of 75 participants (9%) who received acarbose developed type 2 diabetes, compared with 18 of 65 participants (28%) who received no intervention. Treatment with acarbose neither reduced nor increased the risk of death from any cause, death from heart disease, serious side effects, stroke, or heart failure [110].

Agents approved for weight loss have been shown to decrease the incidence of diabetes in those with prediabetes [111,112]. However, as stated, none are FDA-approved for diabetes prevention [13]. There are five medications (orlistat, phentermine/topiramate, bupropion/naltrexone, semaglutide, and liraglutide) approved by the FDA for the long-term treatment of obesity [110]. These medications have been shown to be modestly effective in promoting initial weight loss, with improved results when used in combination with lifestyle changes [110,113]. Another medication, lorcaserin, was withdrawn from the U.S. market in February 2020 [105,110].

Orlistat is available by prescription (as Xenical) or over-the-counter in half-strength under the brand name Alli. It acts by deactivating gastric and pancreatic enzymes, thus preventing the absorption of fat through the gastrointestinal wall [110]. Gastrointestinal side effects, such as bloating, gas, and oily stools, account for a high rate of discontinuation.

Phentermine/topiramate (extended-release) combines an anorexiant and an anticonvulsant to improve short-term weight-loss outcomes in patients who have already attempted lifestyle changes (i.e., calorie-restricted diet and increased physical activity) [105]. Eligible patients will have a BMI ≥30 or a BMI ≥27 with a weight-related comorbidity [105]. The medication is contraindicated in persons with glaucoma and hyperthyroidism and is not recommended for patients with a recent history of stroke or heart disease [105]. It is also teratogenic, with proven fetal defects with first trimester exposure. Therefore, all women of childbearing age should use effective contraception consistently while taking the drug and have documented proof of a negative pregnancy test prior to the initiation of treatment and every month thereafter [105].

Bupropion/naltrexone is approved as a treatment option for chronic weight management in conjunction with a reduced-calorie diet and increased physical activity [105]. As with phentermine/topiramate, eligible patients will have a BMI ≥30 or a BMI ≥27 with a weight-related comorbidity [105]. The dosage is gradually titrated up, starting with one tablet (naltrexone 8 mg/bupropion 90 mg) once daily in the morning for one week and increasing one daily tablet each week for four weeks. The maintenance dose is two tablets twice daily [105]. If 5% of initial body weight has not been lost after 12 weeks, the medication should be discontinued [105]. Any patient taking bupropion should be carefully monitored for suicidal ideation and behaviors [105]. This medication may also increase blood pressure and heart rate and is contraindicated in patients with hypertension. It is also contraindicated in patients with a history of seizures, who are taking another bupropion-containing medication, or who are pregnant [105].

The GLP-1 receptor agonist liraglutide also is approved by the FDA for chronic weight management. Traditionally used to treat diabetes, liraglutide has been found to aid in appetite suppression and weight loss [114]. Eligible patients will have a BMI ≥30 or a BMI ≥27 with a weight-related comorbidity [105]. The dosage of liraglutide used for weight management (3 mg) differs from the dose used in diabetes medication regimens (1.8 mg), and the safety and efficacy of this higher dose for the treatment of diabetes has not been established [114]. If 5% of initial body weight has not been lost after 12 weeks, the medication should be discontinued [105]. This medication is contraindicated in pregnant women and in those with a personal or family history of thyroid cancer [105,110].

In 2021, the FDA approved semaglutide injection for chronic weight management in adults with obesity (BMI ≥30) or overweight (BMI ≥27) with at least one weight-related condition (e.g., hypertension, type 2 diabetes, hyperlipidemia) [115]. This agent is a glucagon-like peptide-1 (GLP-1) receptor agonist and is intended to be used in conjunction with lifestyle changes. When used for weight management, semaglutide is administered subdermally at a dose of 2.4 mg once weekly [115].

In addition, setmelanotide injection, a melanocortin 4 receptor agonist, is approved for use in cases of rare genetic mutations resulting in severe hyperphagia and extreme obesity [13,110].

Tirzepatide was approved for type 2 diabetes treatment by the FDA (as Mounjaro) in 2022 [105]. In 2023, the FDA also approved the agent for chronic weight management, with the same indications as semaglutide [105]. Tirzepatide acts as a dual incretin agonist of GLP-1 receptor and glucose-dependent insulinotropic polypeptide (GIP) receptor and is dubbed the "twincretin" [105]. The initial dose is 2.5-mg subcutaneous injection once weekly for four weeks, at which point it is increaed to 5 mg once weekly. Further dose escalation in 2.5-mg/week increments (up to a maximum weekly dose of 15 mg/week) is possible every four weeks [105].

On a broader level, a public health approach to fighting childhood obesity is needed. This should include school programs that integrate nutrition, physical education, and sociobehavioral approaches to promote healthy lifestyle choices among youth. School lunch programs should offer healthy choices and strictly limit foods that are high in fat and sugar from cafeterias, food courts, and vending machines. School-based exercise programs are also very important in promoting the health of children. Because working parents may not have time to exercise with their children and many children do not live where it is safe to play outside without adult supervision, children need the opportunity for physical activity during the school day.

The battle against childhood obesity should extend beyond the school into the broader public health sector. Public health education should be family-centered and provide children with knowledge and avenues for behavioral change. These educational approaches should be multicultural in nature, taking into account the various health beliefs and dietary patterns of the populations directly affected by current rates of obesity and diabetes. Information about state and local programs focused on promoting health efforts are available on the CDC website at https://www.cdc.gov/nccdphp/dnpao/state-local-programs/index.html.

Diabetes is an urgent issue in the Latin American/Hispanic communities. Hispanic adults are 70% more likely than non-Hispanic White adults to be diagnosed with diabetes [131]. Rates of complications of diabetes are also higher among this group. Abdominal obesity and insulin resistance greatly increase the risk for metabolic syndrome in this population.

In Latin American/Hispanic cultures, the family unit is very important and the needs of the family are placed above the needs of the individual. Winning confianza is important in establishing the nurse-patient relationship. This is achieved by showing respect for the culture and willingness to engage in non-healthcare-related conversation with the patient. A warm, caring, and personable manner is valued. Latino/a clients may perceive a neutral attitude from the healthcare provider as a negative attitude. This population tends to prefer teaching methods that involve storytelling and other audio presentations to printed materials [127].

The traditional Hispanic diet is high in fruits, vegetables, and fiber, and low in fat. However, acculturation to the American diet has changed traditional preferences and practices to a less healthy style of eating. Healthy choices most likely to appeal to this population include [128]:

According to data from the CDC, 49.5% of Hispanic Americans are physically inactive, compared with 38.9% of White Americans [132]. A small study of Hispanics has suggested that a group-dancing program is a culturally appealing form of exercise among Mexican Americans [133].

Diabetes strikes 1 out of every 13 Black Americans, and about one-third of these individuals are unaware they have the disease [134]. African Americans with diabetes are more likely to develop serious long-term complications and suffer greater associated disability than other racial/ethnic groups [134]. Genetic predisposition plays a major role in the higher incidence of IGT and diabetes in African Americans. As for body type, African Americans have a greater tendency for upper-body or central obesity, which is a known risk factor for metabolic syndrome.

African Americans have a high prevalence of cardiovascular risk factors that may be reduced with lifestyle modification. These include obesity, hypertension, sedentary lifestyle, and tobacco use [127]. Unfortunately, studies have indicated that African Americans are less likely to participate in health screening programs. This is due in part to poor access, but may also stem from cultural and historical factors, such as mistrust of the healthcare system stemming from a history of inequitable treatment [127].

Studies have been performed to determine the best way to help African Americans make lifestyle changes for preventive health. One study concluded that being involved in group support and education sessions to promote weight loss was not effective for this population. This same study also showed that keeping food diaries did not help African American patients lose weight [78]. These findings suggest that alternate approaches to weight loss should be considered when working with African American patients.

Traditional food preferences of African Americans are regional, and many White Americans in the southern United States share these food preferences. They include [128]:

This group encompasses people from a wide geographic area, consisting of many different subcultures. However, there are a few similarities in food preferences and cultural traditions that tend to occur across these cultures.

The American Diabetes Association recommends a lower body mass index cut point (23 rather than 25) for screening overweight or obese Asian Americans for prediabetes and type 2 diabetes to reflect the evidence that this population is at an increased risk for diabetes at lower BMI levels relative to the general population.

(https://diabetesjournals.org/care/issue/47/Supplement_1 Last Accessed: January 10, 2024)

Level of Evidence: B (Supportive evidence from well-conducted cohort and/or case-control studies)

The incidence of diabetes among Asian Americans has increased more rapidly among those who have lived in the United States for a longer period of time than among new immigrants or those living in Asia [127]. Japanese individuals living in Seattle have diabetes prevalence four to five times that of those living in Tokyo [127]. Use of BMI is not as reliable a tool for predicting diabetes risk in Asian populations, as they tend to develop insulin resistance and type 2 diabetes at much lower indices [13,135]. The International Diabetes Federation has determined lower measures of waist circumference for determining health risk in Asian populations [135]. A systematic review of dietary self-management of diabetes among Asian Americans identified themes, including cultural beliefs about food, that characterize the cultural perspectives and experiences that influence diabetes self-management [136]. Patients reported receiving dietary recommendations that did not align with their beliefs about food as medicine and a source of balance in life and that recommendations to remove refined carbohydrates (e.g., rice) from their diets caused them to feel isolated from familiar and shared food habits and practices [136].

In general, white rice is a basic and important component of Asian diets. Virtually every Asian meal includes white rice, accounting for up to 75% of the diet [137]. Because greater consumption of white rice is associated with higher risk for diabetes and can significantly raise blood glucose in people with diabetes, this cultural preference, as stated, presents a significant challenge for many. A review of four studies involving more than 352,000 people from China, Japan, the United States, and Australia found that people who ate three to four servings of white rice daily were 1.5 times more likely to have diabetes than those who ate the least amount of rice. For every additional large bowl of white rice a person ate each day, the risk rose 10%. The link was found to be stronger for people in Asian countries, who eat an average of three to four servings of white rice per day [138]. In contrast, a brown rice intake of two or more servings per week has been associated with a lower risk of diabetes, supporting the recommendation that most carbohydrate intake should come from whole grains [139].

Traditional Asian food preferences include:

From a cultural standpoint, many Asian cultures do not value strenuous physical activity, focusing instead on martial arts and tai chi. Family values influence childhood participation in organized sports and overall physical activities, which in turn shapes the role of exercise in the management of diabetes [140]. Additional research is necessary to determine an appropriate, yet culturally sensitive, exercise intervention strategy for this population [141].

Dietary practices among Asian Indians vary according to region of origin within India and the form of religion practiced. For many Asian Indians living in the United States, the traditional low-fat, high-fiber diet has evolved to include more saturated fat and fast food. Traditional dietary preferences include:

Native Americans are a diverse population, representing several hundred different groups that have settled on the North American continent. In addition, there are Alaska Natives who are distinct from Indian tribes of the continental United States. Many Native Americans live on reservations in rural areas, but just as many live in urban areas. Because each tribe has a unique history, geographic location, social system, cultural styles, and traditions, only general aspects of this group are presented here.

American Indian/Alaska Native adults are almost three times more likely than non-Hispanic White adults to be diagnosed with diabetes and 2.3 times more likely to die from diabetes [142]. The highest rates of diabetes are reported among the Pima Indians of Arizona, where 50% of the adult population has diabetes [143]. Genetic predisposition along with modernization and dietary changes are responsible for the increased rate of diabetes among this population.

In general, Native Americans may not be comfortable disclosing personal information, especially to an outsider. Having a "problem" may be perceived as placing oneself lower on the rung of power. Using an aggressive approach to problem-solving during the healthcare encounter can damage the relationship. Appropriate teaching methods for this population include one-to-one instruction using demonstrations, pictures, and other visuals.

Food is an important part of most Native American cultures and is used in many cultural rituals, spiritual ceremonies, and social activities. The traditional diet was very healthy, but poverty and modernization have led to more reliance on foods such as lard, sugar, and white flour.

Traditional food preferences of Native Americans depend upon geographic location and may include:

The Health Belief Model (HBM) provides the basis for widely used strategies that assist patients in making health behavior change [146]. Originally developed in the 1950s, the HBM has been expanded and increasingly popularized over the past two decades. Based on psychologic theory, the HBM examines factors that motivate people to change health behaviors and strives to understand what makes them take action to prevent or manage illness.

Perceived susceptibility is the first construct of the HBM. This may be reflected by the patient considering "What is the likelihood that I will get diabetes?" Patients who believe the risk is low will be less likely to make changes to prevent diabetes. Educating patients about the risk factors for diabetes will help them understand their susceptibility.

Perceived severity refers to how serious a patient believes the condition to be. Patients may consider how diabetes could affect their health, quality life, and functional ability. Of all of the constructs of the HBM, perceived severity has been found to be the least powerful predictor of behavior change.

Perceived benefits refer to a patient's belief about the advantages of taking action. For example, in addition to recognizing the health benefits of weight loss, a patient may also expect it to bring psychologic, emotional, and social benefits. Patients may be motivated to make change by stating the benefits they perceive weight loss would bring and having these reflected back to them.

Perceived barriers are the perceived negative aspects of behavior change; these are things that may impede change. A patient may feel that healthy eating is too complicated and boring. Exploring barriers and ways to overcome them are an important part of the behavior change process.

Cues to action are the "wake-up call" that prompts a patient to seek change. A call from the doctor reporting elevated blood glucose may give a patient a reason to think about changing his or her eating habits. Readiness is an important part of the behavior change process. It is important to explore the degree of readiness that patients have and learn appropriate responses to their self-identified level of readiness. These strategies will be discussed in detail later in this course.

Self-efficacy refers to a person's sense of confidence in his or her own ability to perform a behavior or a set of behaviors. Theoretically, people who are confident that they will be successful are more likely to perform that behavior. A patient's confidence can be boosted with a statement such as, "From what you have told me, I feel that you will be able to make a plan that will work for you."

Assessment of patients' self-efficacy involves asking them how confident they are that they can make the change. If confidence is low, ask them what it would take to make them feel more confident. It is important to negotiate realistic goals and an action plan with which your patient feels confident. Being able to meet a goal increases self-efficacy. If goals and action plans are not achievable, help the patient modify them to become more realistic.

The healthcare professional's role in helping patients change behaviors to prevent diabetes should not be underestimated. Even simply providing evidence-based advice and culturally sensitive education can result in modest changes in health behaviors, such as those related to diet modification and tobacco cessation. However, patients who passively receive education and advice are not as likely to make lasting behavior change as are those who actively participate in the process of change. Effective intervention to support behavior change usually requires multiple encounters that include more than just passively receiving advice. Patients must learn how to translate awareness into plans, and plans into action. There are several effective strategies for helping them do this.

The U.S. Preventive Services Task Force has developed the Five A's protocol, a widely used framework for supporting behavior change in clinical settings [147]. The Five A's protocol can help structure an approach to help patients make health behavior changes. The Five A's are [147]:

Losing weight, eating differently, and increasing exercise are significant behavior changes for many people with prediabetes. Although it is tempting to think of change as a discrete event, it is actually an unfolding process that happens over time. "Stages of change" refers to the theory that people move through a predictable, though not always linear, series of stages as they give up unhealthy behaviors and replace them with health-enhancing behaviors. James Prochaska's Transtheoretical Model of Behavior Change, which has been widely used in diabetes self-management and smoking cessation, describes the stages of behavior change [153,154]. Prochaska identified six stages that people go through as they attempt behavioral lifestyle changes, from precontemplation, during which the person does not intend to change within the next six months, to maintenance, when healthy behaviors have been practiced for at least six months. For each stage of change, certain interventions on the part of the healthcare provider are recommended [153].

If patients need to lose weight, eat differently, and/or exercise more and they are ready to make these changes, be prepared to help them formulate a realistic plan for accomplishing this. Having specific goals increases the likelihood of performing a behavior and is associated with improved health-related behavior. Successful preventive health care requires a collaborative approach to choosing behavior change goals and identifying the steps to achievement. Start the goal-setting process by asking patients what they would like to start doing to improve their health [155].

While many patients might concur that some degree of lifestyle change would be beneficial, a significant number will be ambivalent about taking concrete action. Some will be entirely resistant to change, demonstrating a lack of readiness by denying the problem or any need to make behavior change. Others may already be taking action but still need to maintain the changes over time. Motivational interviewing is a dynamic strategy for guiding patients through all of these stages of change. William R. Miller originally developed this method in 1983 to help problem drinkers and was later joined by Stephen Rollnick to formalize this revolutionary concept in promoting health behavior change in other areas [156,157].

When patients have a condition such as prediabetes, in which lifestyle modification is the primary treatment, simply giving advice is usually not enough to instigate significant change. In fact, when working with patients to make behavior change, one should expect one's role as the authority figure to diminish while their authority increases. This is because patients usually have their own answers when it comes to lifestyle modification, although they are often unacknowledged. Patients usually know what they need to do and may even have some ideas for how they might do it, but they often resist or feel ambivalent about taking action. What they need is help in becoming aware of their own resources, feeling more confident in their ability to change, and learning to put their ideas into action. Therefore, counseling a patient on health behavior change means healthcare professionals surrender the role of expert in exchange for becoming a guide.

Motivational interviewing is a therapeutic communication strategy that facilitates behavior change by focusing on a person's current interests and concerns. It creates an atmosphere in which the patient generates his or her own reasons for change. Motivational interviewing is appropriate to use in any situation in which behavior change is indicated, including with people who are resistant to change and those who lack the confidence or motivation to make change.

Motivational interviewing recognizes that there is a natural human tendency to resist being told what to do by others and that it is difficult for people to break through well-established behavioral rituals. Failure to change health-related behaviors is often in conflict with the healthcare providers' inclination to help, heal, and prevent harm. However, people who engage in unhealthy behaviors are usually already aware of what they should be doing instead.

The process of motivational interviewing identifies people who are resistant to change and allows the provider to "roll with the resistance" rather than challenge it. This intervention capitalizes on a person's ambivalence about behavior change, exploring the discrepancy between personal goals and actual behavior. Importantly, it evokes a person's own reasons for making behavior change and his or her resources for making it happen.

Patients resist behavior change for many reasons. One reason is that it is usually easier to maintain established habits than to change them. People may also be afraid of failure, or they may have anger or a lack of confidence in their ability to change. Indicators of resistance to change may include changing the subject during a discussion, arguing, or denying the problem. When patients are clearly not ready to make behavior change, resist the urge to try to talk them into it, as this runs the risk of putting them on the defensive and making them argue in favor of staying the same. When patients repeatedly argue against change, the undesired behavior is actually reinforced. At this point, it is best to remain nonjudgmental and to keep the lines of communication open for future discussion. Examples of responses to a patient who is not willing to change are:

Many patients are ambivalent about changing. This means that they recognize the need for change and would like to do it, but they are also keenly aware of the advantages of staying the same. Ambivalence about behavior change represents both an opportunity and a hindrance. For example, the patient knows that being overweight is unhealthy but does not want to change his or her eating habits, saying, "I would like to lose weight, but I love to eat!" Notice that the patient first thinks of a reason to change, but cancels it out by thinking of the reasons not to change. These types of statements are known as "change talk." Because the patient has said he or she would like to lose weight, the perceived benefits and hypothetical solutions can be explored. The goal is to raise the patient's level of readiness to change by discovering and amplifying his or her own reasons and ways to do it. In this scenario, patients may be encouraged to talk about why they would like to lose weight and the benefits they would reap from it. For example, one could say, "Although you love to eat, you feel there would be some advantages to losing weight. What would be some of those advantages?" By having the patient state the benefits of losing weight, the patient's own change talk may be elicited. People are more influenced by what they hear themselves say than by what others tell them.

When patients are ambivalent, avoid giving them the opportunity to present arguments about why they do not want to change. A better alternative is to help patients voice their own arguments in favor of change. According to Rollnick et al., "If you are arguing for change and your patient is resisting and arguing against it, you're in the wrong role. You are taking all the good lines. It is the patient, rather than you, who should be voicing the arguments for behavior change" [156]. Change talk may be elicited from patients by asking them what they might like to change and how they might see themselves doing it.

Motivational interviewing involves a collaborative relationship that empowers patients to determine how they can make a difference in their own health. It is a skilled process that requires special training to realize its full potential. However, anyone can incorporate some of the basic tenets of motivational interviewing into their current practice by following these steps:

Ask open-ended, empowering questions. (What would you like help with today?)

Listen more than speak, and avoid interrupting the patient. (Go on…)

Summarize what the patient says. (From what you have told me, you are worried about how prediabetes will affect your health.)

Provide information in a neutral manner. (Now that you know what the experts recommend for exercise, how do you think that would fit into your life? Your weight today is 178 pounds. What do you think about that?)

Offer choices and negotiate the agenda. (Of the things that you can do to lose weight, which one(s) would you like to work on most?)

Listen for and respond to change talk. (It sounds like you have been thinking about exercising more. How would exercise make your life better?)

Evoke patients' own reasons for change. (What benefits might you gain from getting more exercise? How important do you think this is?)

Explore ambivalence. (What do you like about the way things are now? What benefits would you get from exercising more?)

Summarize what the patient is telling you. (On one hand, I hear you saying that it would take some work on your part to exercise regularly, but on the other hand, you would feel better about yourself if you did it.)

Assess readiness to change. (How ready do you feel to become more physically active? On a scale of 0 to 10, how ready are you to start getting more exercise? Why did you choose that number?)

Help your patient explore solutions. (What has worked for you in the past? What could you see yourself doing now? What would you like about doing this?)

Assess confidence. (On a scale of 0 to 10, how ready are you to start exercising? Why did you choose that number? What would it take for you to have a higher number on this scale?)

Roll with resistance and honor autonomy. (The final decision for change is up to you. For now, it sounds like the benefits of staying the same are greater than the benefits of changing. How do you feel about keeping things the way they are?)

Affirm the patient's statements and support self-efficacy. (You have come up with some good ideas for how you can get more exercise. I feel confident that if you do choose to exercise, you will find a way to make it happen.)

Education to prevent diabetes is taking place on a national level. Under the new healthcare reform legislation, the CDC has authorized the establishment of a National Diabetes Prevention Program [163]. The DPP and follow-up studies have clearly demonstrated that lifestyle modification is the critical element in preventing progression from prediabetes to type 2 diabetes. CDC-recognized lifestyle change programs are a key component of the DPP [164]. Multiple studies suggest that intensive interventions, taking place over multiple sessions, are most effective [2,109,165]. Clinical experts, such as registered dietitians and nurses, as well as trained peers and laypersons appear to be efficacious in delivering this education [165,166]. The Healthy Living Partnerships to Prevent Diabetes (HELP PD) study was a community-based lifestyle intervention program modeled after the DPP. The program design included [165]:

In this study, the control group received care consisting of two visits with a registered dietitian and a quarterly newsletter with tips for lifestyle changes. Results included a decrease in blood glucose levels of more than 4 mg/dL in the study group, compared to 0.3 mg/dL reduction in the control group [165]. The intensively treated group also achieved a weight loss of 7.3% and a 5.9 cm decrease in waist circumference after one year. The control group lost only 1.3% of body weight and had a decrease in waist circumference of only 0.8 cm.

One study examined the impact of DPP intervention on blood glucose and adiposity beyond 12 months of follow-up. This randomized controlled trial compared a 24-month lifestyle weight-loss program to an enhanced usual care condition in participants with prediabetes. The lifestyle weight-loss program sought to induce 7% weight loss at six months that would be maintained over time through decreased caloric intake and increased physical activity. The usual care group received two visits with a registered dietitian and a monthly newsletter. Results revealed that the lifestyle weight-loss program participants experienced greater decreases in fasting glucose (-4.35 mg/dL); body weight (-4.19 kg); and waist circumference (-3.23 cm) [167].

In another pilot study, people with prediabetes in rural Montana participated in a prevention program implementing the DPP lifestyle interventions through a 16-week telehealth program [166]. In this program, education was delivered by video teleconferencing to participants. Coaches and participants at both sites could see and hear each other through videoconferencing equipment. The program consisted of 16 weekly core curriculum sessions followed by six monthly after-core sessions [166]. Results of this pilot study demonstrated that a telehealth program could be just as effective as face-to-face participation. Participants in both groups had similar results, including increasing their physical activity levels and achieving a 7% weight loss. Other alternatives to intensive one-to-one counseling could include follow-up by telephone, email, or Internet-based interactive programs.

The criterion standard for preventing diabetes in high-risk populations is intensive lifestyle intervention over an extended period. However, this type of program is labor- and resource-intensive and requires dedicated staff. Limited resources can influence the feasibility of funding and developing new programs.

Analysis of the DPP has shown that the interventions to prevent progression to type 2 diabetes in high-risk people can be cost effective from both societal and health systems perspectives. While the design of the DPP comprised intensive individual coaching and follow-up, group education sessions will increase its cost effectiveness. For diabetes self-management, group education is known to be as effective as individual education, and this is most likely true for prediabetes education as well[39].

Most studies on the effectiveness of diabetes prevention programs have examined intensive, multisession programs. More research is needed to explore the efficacy and cost effectiveness of diabetes prevention programs that use alternate formats. There has been limited research on the effectiveness of single-session classes. One study, however, demonstrated that a single session of motivational interviewing by telephone had a positive effect on lipid profiles and physical activity level[168]. A systematic review and meta-analysis found that the use of mobile text messaging for conveying type 2 diabetes interventions was effective for glycemic control[169]. Additionally, a feasibility study found that sending short text messages in conjunction with conventional diabetes treatment improved glycemic control and positively influenced other aspects of diabetes self-care in individuals with type 2 diabetes[170].

Time limitations in healthcare practice are generally ubiquitous, and all of the interventions for diabetes prevention may require more than a single 15-minute or brief messaging interaction. Efficiency can be maximized by using resources wisely. Consider how the rest of the healthcare team can assist the patient, and be familiar with other resources within the healthcare setting. Consider a referral to a dietitian or other healthy lifestyle resource, such as weight management, healthy eating, and exercise classes. Become familiar with community-based resources for diabetes prevention, weight loss, exercise, and general health promotion. Utilize the numerous online resources; many of them are interactive, which can enhance the patient's experience. Refer to theResourcessection of this course for additional information.

Interest in and understanding of health literacy has grown tremendously over the last 20 years. It has been an important component of the Healthy People initiative as well as Title V of The Patient Protection and Affordable Care Act of 2010, which defines health literacy as the degree to which a person can obtain, communicate, process, and understand basic health information and services to make appropriate health decisions [171]. Healthy People 2030 contains an updated definition that includes personal health literacy as well as organizational health literacy. The new definitions emphasize the ability to use health information rather than to just understand it; focus on the ability to make "well-informed" decisions as opposed to "appropriate" ones; incorporate a public health perspective; and acknowledge that organizations have a responsibility to address health literacy [171].

The government reports that nearly 90% of Americans have difficulty utilizing the health information that is routinely provided in healthcare facilities and in the media [172]. This is unsurprising when one considers that most Americans have never had a course in anatomy or physiology and that the average high school graduate has had a total of one health sciences class. Also notable is that only 12% of English-speaking adults in the United States have proficient health literacy skills [172].

Low health literacy has been associated with increased usage of the healthcare system. United Health Group reports that improving health literacy could prevent nearly one million hospital visits and save more than $25 billion each year [173]. Effects of low health literacy include improper medication use, nonadherence to prescribed regimens, inability to make appropriate healthcare decisions, and ineffective self-care behaviors [174]. In people with diabetes, low health literacy has been associated with poor glycemic control, an increase in diabetic retinopathy, and hypoglycemia [175,176]. A study conducted by the U.S. Department of Education found that adults who self-report the worst health also have the most limited literacy, numeracy, and health literacy skills [177].

Numeracy is a part of literacy that includes concepts having to do with numbers and basic mathematical functions. It includes "the ability to access, use, interpret, and communicate mathematical information and ideas, to engage in and manage mathematical demands of a range of situations in adult life" [178]. Numeracy is important for patients with diabetes and prediabetes, in which there is a need to read food labels, calculate nutrient value percentages, and interpret blood glucose values, among other skills.

Following research completed since 1990, the USDHHS has formulated the National Action Plan to Improve Health Literacy, an initiative to restructure the ways health information is created and disseminated in the United States. It calls upon multiple sectors, such as policymakers, organizations, communities, and individuals, to improve health literacy [172]. The National Action Plan is based upon the premise that improved health literacy supports patient-centered care. Patients who have access to understandable health information are more empowered to take appropriate action with their health.

There are many ways that healthcare professionals can easily incorporate improved health literacy into professional practice. First, make it a point to use plain language, both verbally and in writing, when interacting with patients. Avoid medical terms and jargon as much as possible. For example, "high blood sugar" is simpler than "elevated blood glucose" and "heart disease" or "heart problems" are simpler than "cardiovascular complications." The CDC's Health Literacy website contains information about guidelines, laws, and standards for health literacy and plain language that can help healthcare professionals create and use health information that is accurate, accessible, and actionable [179].

Visual aids can improve patients' understanding as well. Food models and pictures can be used, including the plate method. Understand that most adults need to hear something more than once before being able to commit it to knowledge. Therefore, use repetition and vary the way the same concept is explained. Many times, the amount of information healthcare professionals are expected to disseminate can be overwhelming. If healthcare professionals are overwhelmed by the information, it is safe to assume patients will be as well. Patients recall only about one-half of the health information provided to them [180]. Therefore, provide related information in "chunks" and limit new information to one to three "need to know" concepts at one time. This provides an excellent opportunity to apply skills in providing patient-centered care, asking patients what they would like to work on most. Continue to check for understanding and encourage questions.

The teach-back method is recommended for improved health literacy [180]. This is a way to clarify patients' understanding of what has been taught. Teach back consists of asking patients to recount, in their own words, what they heard. This will allow for assessment of misunderstandings and gaps in learning. When using teach back, avoid making the patient feel threatened by framing the request in a way that centers any inadequacies on the healthcare system or provider. For example, one could say, "I would like to make sure I explained the plate method well to you. Can you tell me, in your own words, how you would use it to help you decide what to eat?"

Verbal instructions should be supplemented with written material. However, written material should be designed for the majority and follow appropriate guidelines for health literacy. Health information translated to other languages from English should maintain the health literacy standards of the original piece. Health education literature should also look easy to read, having a font size of 12 to 14 points. Written materials should have plenty of white space on the paper. About 25% to 35% of the page should be white, and margins should be no smaller than one-half inch. Graphics can help enhance literacy if they are appropriate in content and size and to the meaning to the document.

Culturally appropriate programs have proven effective for diabetes education and similar programs should likewise be appropriate for prediabetes education. Project Dulce is a community-based diabetes education program in San Diego, California, that uses bilingual peer educators, known as promotoras, to educate and support members of their own cultural or ethnic group [181]. The promotoras are trained lay members of a nurse-led healthcare team that adheres to clinical standards of diabetes disease management. The Project Dulce team collaborates with the participants' own healthcare providers in ensuring that care and education follows established protocols. Originally developed for the Hispanic/Latino population, Project Dulce has now been adapted for the African American, Filipino, and Vietnamese populations.

Other culturally relevant programs are currently being tested in different parts of the United States [182]. The Health Native Community Partnership is an organization devoted to empowering Native Americans to take action to promote the wellness of themselves and their community. Native Lifestyle Balance is a diabetes prevention program based on the DPP with cultural adaptations for this group [183].