1 . A Black adult with a body mass index (BMI) of 28 would be considered
| A) | | underweight. |
| B) | | healthy weight. |
| C) | | overweight. |
| D) | | obese. |
BMI DEFINITIONS OF WEIGHT
| Weight Category | BMI Definition
(kg/m2) |
|---|
| Adult | Adult, East Asian | Pediatrica |
|---|
| Underweight | <18.5 | <18.5 | <5th percentile |
| Normal | 18.5–24.9 | 18.5–22.9 | 5th–85th percentile |
| Overweight | 25–29.9 | 23–24.9 | ≥85th percentile |
| Class I obesity | 30–34.9 | 25–29.9 |
Obesity: ≥95th percentile
|
| Class II obesity | 35–39.9 | 30–34.9 |
| Class III obesity (severe obesity) | ≥40 | ≥35 | Severe obesity: ≥120% of the 95th percentile |
| aBased on sex-specific
BMI for age |
2 . In 2023, the AMA adopted a policy that recognizes the issues with BMI measurement and suggests that it be used in conjunction with other valid measures of risk. Which of the following is considered a valid measure of risk?
| A) | | Visceral fat |
| B) | | Body composition |
| C) | | Genetic or metabolic factors |
| D) | | All of the above |
No support text associated with this question.Click to Review
3 . During 2017–2018, which racial/ethnic group had the highest age-adjusted obesity prevalence in the United States?
| A) | | Hispanic Americans |
| B) | | Non-Hispanic Black Americans |
| C) | | Non-Hispanic Asian Americans |
| D) | | Non-Hispanic White Americans |
During 2017–2018, non-Hispanic Black Americans (49.9%)
had the highest age-adjusted obesity prevalence, followed by Hispanic Americans (45.6%),
non-Hispanic White Americans (41.4%), and non-Hispanic Asian Americans (16.1%), who also
have lower BMI thresholds for adiposopathic (adipocyte and adipose tissue dysfunction)
complications [1,29].
4 . A 5-point increase in BMI is strongly associated with increased risk of all of the following, EXCEPT:
| A) | | Thyroid and colon cancers in men |
| B) | | Endometrial and gallbladder cancers in women |
| C) | | Pancreatic and stomach cancers in East Asian individuals |
| D) | | Esophageal adenocarcinoma and renal cancers in both sexes |
Excessive body fat is a cause of 13 cancers, including
esophageal, gastric, cardiac, colorectal, liver, gallbladder, pancreas, meningioma,
postmenopausal breast, endometrium, ovary, kidney, thyroid, and multiple myeloma [47]. A 5-point increase in BMI is strongly
associated with increased risk of thyroid and colon cancers in men, endometrial and
gallbladder cancers in women, and esophageal adenocarcinoma and renal cancers in both sexes
[46]. From 2004 to 2015, the prevalence of
these cancers increased 7% while cancers not known to be related to excessive body fat
decreased 13% [46]. Overweight- and
obesity-related cancers account for about 40% of all cancers. With approximately 70% of
adults overweight or obese, promoting the maintenance of weight loss to decrease cancer risk
is critical [47].
5 . Basal energy expenditure is defined as
| A) | | exercise and non-exercise activity. |
| B) | | work-time (occupational) or leisure-time energy expenditure. |
| C) | | the sum of basal energy expenditure and activity energy expenditure. |
| D) | | the minimum energy required to maintain vital physiological functions. |
ETIOLOGY OF THE OBESITY EPIDEMIC
Understanding the relative contribution of lower energy
expenditure to the obesity epidemic is a crucial task that requires accurate measurements of
energy expenditure [66,67,68]. The terms used in discussions of this concept should be clearly defined
[70,71,72]:
Basal energy expenditure: Also known as resting energy expenditure or basal
metabolic rate, the minimum energy required to maintain vital physiological functions
Activity energy expenditure: Exercise and non-exercise activity
Physical activity: Work-time (occupational) or leisure-time energy expenditure
Total energy expenditure: Expressed in calories/day, the sum of basal energy
expenditure and activity energy expenditure
6 . Increasing activity levels may bring diminishing returns due to
| A) | | decreased activity intensity over time. |
| B) | | compensatory responses in nonactivity energy expenditure. |
| C) | | a predisposition to adiposity because they are weaker energy compensators. |
| D) | | All of the above |
ETIOLOGY OF THE OBESITY EPIDEMIC
Increasing activity levels may bring diminishing returns
due to compensatory responses in nonactivity energy expenditure [66]. In 1,754 adults with DLW measured seven
years apart, only 72% of the extra calories burned during activity translated into extra
calories expended that day, because the body offset the calories burned in activities by
28%. Among those with BMI ≥34, compensation of burned activity calories increased to 46%
[72].
7 . Which of the following statements regarding energy balance is FALSE?
| A) | | The small storage capacity for fat can cover overnight energy needs during sleep. |
| B) | | As a substrate for energy metabolism, fat is last in the hierarchy that determines fuel selection. |
| C) | | Excess energy is stored as fat in adipose depots, carbohydrate (as glycogen) in liver, or protein in muscle. |
| D) | | The energy density of adipose tissue is nearly 10-fold greater than liver (glycogen) or muscle (protein). |
THE REGULATION OF BODY WEIGHT
Excess energy is stored as fat in adipose depots,
carbohydrate (as glycogen) in liver, or protein in muscle. The energy density of adipose
tissue is nearly 10-fold greater than liver (glycogen) or muscle (protein). The small
storage capacity for carbohydrate can cover overnight energy needs during sleep. The
larger energy stores of fat are mobilized to cover longer-term energy shortages [70,102,103].
However, as a substrate for energy metabolism, fat is
last in the hierarchy that determines fuel selection; it is mostly stored before oxidation
and is less likely to be oxidized than carbohydrate or protein. Body-fat mass and
oxidation of dietary fat are inversely related—higher fat mass lowers the oxidation rate
of dietary fat [70,102,103]. Energy expenditure is the sum of ATP generated by oxidizing monomers
to drive physiological processes.
8 . The Obesity Medicine Association (OMA) has identified four pillars of obesity care. These pillars are
| A) | | psychotherapy, pharmacotherapy, environmental interventions, and lifestyle changes. |
| B) | | healthful nutrition, physical activity, behavior modification, and medical management. |
| C) | | cognitive-behavioral therapy, dialectical behavioral therapy, exercise therapy, and insulin. |
| D) | | antiobesity medications, surgical interventions, hormone therapy, and medical nutrition therapy. |
OVERVIEW OF CLINICAL MANAGEMENT
The OMA states that obesity is a serious and
multifactorial disease that requires patient access to comprehensive care, including the
four pillars of healthful nutrition, physical activity, behavior modification, and medical
management with antiobesity medications and surgical interventions. Comprehensive care of
obesity is not only about reducing weight but also about improving the health of patients
[122].
9 . Which of the following antidepressants in considered to be weight-reducing?
| A) | | Paroxetine |
| B) | | Bupropion |
| C) | | Mirtazapine |
| D) | | Amitriptyline |
OVERVIEW OF CLINICAL MANAGEMENT
OBESOGENIC MEDICATIONS AND WEIGHT-NEUTRAL OR -REDUCING ALTERNATIVES
| Clinical Condition or Drug Class | Weight-Promoting | Weight Neutral | Weight-Reducing |
|---|
| Type 2 diabetes with obesity |
| Pioglitazone | | Sulfonylureas | | Insulin |
| DPP-4 inhibitors |
| Metformin | | SGLT2 inhibitors | | GLP-1R agonists |
|
| Antidepressants |
| Paroxetine | | Amitriptyline | | Mirtazapine |
| — |
|
| Atypical antipsychotics |
| Olanzapine | | Quetiapine | | Risperidone |
| Ziprasidone | — |
| Anticonvulsants and mood stabilizers |
| Divalproex | | Carbamazepine | | Gabapentin |
|
|
|
| Inflammatory rheumatic diseases | Corticosteroids |
| — |
| DMARDs = disease-modifying antirheumatic drugs,
DPP-4 = dipeptidyl peptidase-4, NSAIDs = nonsteroidal anti-inflammatory drugs, SGLT2
= sodium-glucose cotransporter-2. |
10 . Which of the following is a preferred agent for the patient with bipolar disorder for whom weight loss or maintenance is a concern?
| A) | | Quetiapine |
| B) | | Olanzapine |
| C) | | Ziprasidone |
| D) | | Risperidone |
OVERVIEW OF CLINICAL MANAGEMENT
OBESOGENIC MEDICATIONS AND WEIGHT-NEUTRAL OR -REDUCING ALTERNATIVES
| Clinical Condition or Drug Class | Weight-Promoting | Weight Neutral | Weight-Reducing |
|---|
| Type 2 diabetes with obesity |
| Pioglitazone | | Sulfonylureas | | Insulin |
| DPP-4 inhibitors |
| Metformin | | SGLT2 inhibitors | | GLP-1R agonists |
|
| Antidepressants |
| Paroxetine | | Amitriptyline | | Mirtazapine |
| — |
|
| Atypical antipsychotics |
| Olanzapine | | Quetiapine | | Risperidone |
| Ziprasidone | — |
| Anticonvulsants and mood stabilizers |
| Divalproex | | Carbamazepine | | Gabapentin |
|
|
|
| Inflammatory rheumatic diseases | Corticosteroids |
| — |
| DMARDs = disease-modifying antirheumatic drugs,
DPP-4 = dipeptidyl peptidase-4, NSAIDs = nonsteroidal anti-inflammatory drugs, SGLT2
= sodium-glucose cotransporter-2. |
11 . A patient who achieves 7% reduction in body weight should expect to see
| A) | | type 2 diabetes remission. |
| B) | | remission in obstructive sleep apnea. |
| C) | | improved physical and biomechanical function. |
| D) | | nonalcoholic steatohepatitis (NASH) improvement. |
OVERVIEW OF CLINICAL MANAGEMENT
The estimated weight reduction required to improve
morbidity and mortality outcomes are [3]:
5% to 10% weight reduction: Improved physical and biomechanical function, type 2
diabetes prevention
10% to 15% weight reduction: Cardiovascular disease risk reduction and
remission/reduction in obstructive sleep apnea, hypertension, type 2 diabetes
hyperglycemia
≥16% weight reduction: Type 2 diabetes remission, NASH improvement
12 . All antiobesity medications are considered pregnancy risk factor category
Except for setmelanotide and metreleptin, all antiobesity
medications are approved as adjuncts to a reduced-calorie diet and increased physical
activity for chronic weight management in adults with obesity (BMI ≥30) or overweight (BMI
≥27) with at least one weight-related complication, such as hypertension, type 2 diabetes,
or dyslipidemia [137]. All antiobesity
medications are considered pregnancy risk factor category X drugs and should not be
prescribed to a patient who is pregnant, breastfeeding, or trying to conceive [124].
13 . Which of the following is a common adverse effect of phentermine HCl?
| A) | | Diarrhea |
| B) | | Dry mouth |
| C) | | Hyperactivity |
| D) | | Abdominal pain |
Common adverse effects in clinical trials include dry
mouth (55%) and insomnia (34%), without significant differences in systolic or diastolic
blood pressure, headache, or palpitations between phentermine and placebo groups [131]. Other common side effects include
dizziness, flushing, fatigue, and constipation [92]. Phentermine is not recommended for patients with cardiovascular
disease, and uncontrolled hypertension is a relative contraindication. Phentermine is
available in 8-mg tablets taken three times daily and in 15-mg, 30-mg, and 37.5-mg
capsules taken once daily [131].
14 . Gelesis100 acts
| A) | | by binding to melanocortin-4 receptor (MC4R) in the hypothalamus, downstream of the leptin signaling pathway. |
| B) | | as a transient, space-occupying device in a swallowed capsule that absorbs water to expand and fill up the stomach to induce satiety. |
| C) | | as a centrally acting sympathomimetic, with therapeutic effects mediated through increased levels of norepinephrine in the hypothalamus. |
| D) | | a pancreatic and gastric lipase inhibitor that blocks the lipase-catalysed breakdown and absorption of around 30% of dietary fats. |
Gelesis100 superabsorbent hydrogel is ingested orally,
similar to drugs, but is regulated by the FDA as a class II medical device, because it
acts mechanically as a transient, space-occupying device in a swallowed capsule that
absorbs water to expand and fill up the stomach to induce satiety. Gelesis100 is FDA
approved for patients with BMI 25–40. Recommended dosing is three capsules (2.25 g/dose)
with water before both lunch and dinner [30,123].
15 . Each naltrexone/bupropion tablet contains
| A) | | 8 mg naltrexone and 90 mg bupropion. |
| B) | | 18 mg naltrexone and 9 mg bupropion. |
| C) | | 80 mg naltrexone and 190 mg bupropion. |
| D) | | 90 mg naltrexone and 8 mg bupropion. |
Each naltrexone/bupropion tablet contains naltrexone 8
mg plus bupropion 90 mg. The target maintenance dose of 4 tablets daily (naltrexone 32
mg/bupropion 360 mg) daily is shortened with the prolonged-release formulation (NB32). The
initial dose is 1 tablet daily, increased stepwise to the target of 2 tablets twice daily.
Typical weight loss seen in practice is around 5% to 6% with NB32s [131].
16 . Which of the following agents is a glucagon-like peptide-1 receptor agonist (GLP-1 RA)?
| A) | | Orlistat |
| B) | | Topiramate |
| C) | | Semaglutide |
| D) | | Diethylpropion |
Endogenous GLP-1 has a very short half-life due to
rapid enzymatic degradation by dipeptidyl peptidase-4 (DPP-4). Synthetic analogs modify
the GLP-1 structure to resist DPP-4 by amino acid substitutions in the protein structure
or by attachment to large proteins such as albumin or immunoglobulin [147]. Liraglutide shares a 97% amino acid
sequence similarity with human GLP-1, while semaglutide has a 94% similarity. Compared
with liraglutide, the substantially longer half-life and greater weight loss efficacy of
semaglutide may involve differences in the attached fatty acids [139].
17 . Given the decreased likelihood of obesity in current cannabis users, which medication is being studied for possible antiobesity uses?
| A) | | THC |
| B) | | CBD |
| C) | | Nabilone |
| D) | | Dronabinol |
However, a meta-analysis of data from the National
Epidemiologic Survey on Alcohol and Related Conditions and the National Comorbidity
Survey-Replication found a decreased prevalence of obesity among current users of cannabis
(≥3 days per week) of 14.3% and 17.2%, respectively [185]. Given this decreased likelihood of obesity in current cannabis users,
research has begun to explore how the endocannabinoid system can be manipulated to promote
weight loss and improve metabolic health.
18 . What is the recommended first-line antiobesity medication for obesity management?
| A) | | Liraglutide 1.8 mg daily |
| B) | | Semaglutide 2.4 mg weekly |
| C) | | Orlistat 60 mg three times daily |
| D) | | Phentermine/topiramate 7.5 mg/46 mg daily |
Given the significantly greater weight loss with
semaglutide (15%) than other currently approved antiobesity medications (6% to 10%) and with
69% and 50% of subjects attaining weight loss ≥10% and >15%, respectively, semaglutide
2.4 mg weekly is recommended as the first-line antiobesity medication for obesity management
[131]. Weight-loss goals for most
individuals with obesity should be at least 10% or more, which is now achievable with
current antiobesity medications.
19 . After initiating any antiobesity medication, the weight loss by what point is considered an indicator of treatment response?
| A) | | 2 weeks |
| B) | | 8 weeks |
| C) | | 12 weeks |
| D) | | 24 weeks |
After initiating any antiobesity medication, the weight
lost by 12 weeks is considered an indicator of treatment response. If adherence can be
ensured and 5% weight loss is not achieved after three months, the drug can be given at an
increased dose, combined with another drug, stopped altogether, or replaced with a new drug
[135].
20 . Which of the following antiobesity medications is the least expensive?
| A) | | Orlistat |
| B) | | Liraglutide |
| C) | | Phentermine |
| D) | | Phentermine-topiramate ER |
FDA-APPROVED ANTIOBESITY MEDICATIONS AND RETAIL COST, 2023
| Agent | Typical Maintenance Dose | Average Retail Price, 30-Day Supply |
|---|
| Phentermine | 8–37.5 mg daily | $11.31 |
| Diethylpropion | 75 mg daily | $48.73 |
| Orlistat |
| 60 mg TID (OTC) | | 120 mg TID (Rx) |
|
| ~ $45.00 (Alli) | | $808.06 (Xenical) |
|
| Naltrexone/bupropion ER | 16/180 mg BID | $308.00 |
| Phentermine/topiramate ER | 7.5–15/46–92 mg daily | $231.07 |
| Liraglutide 3.0 mg | Once daily | $1,064.86 |
| Semaglutide 2.4 mg | Once weekly | $1,576.73 |
| Tirzepatide (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg) | Once weekly | $1,059.87 |
| BID = twice daily, OTC = over the counter, Rx =
prescription, TID = three times daily. |
21 . Which of the following metabolic and bariatric surgery (MBS) options is optimally suited for a patient with lower BMI and no metabolic disease?
| A) | | Sleeve gastrectomy |
| B) | | Roux-en-Y gastric bypass (RYGB) |
| C) | | Laparoscopic adjustable gastric banding (LAGB) |
| D) | | Biliopancreatic diversion with duodenal switch (BPD/DS) |
BARIATRIC SURGICAL PROCEDURES AND DEVICES
ASMBS-ENDORSED SURGICAL APPROACHES
| Procedure | Optimally Suited For | Percent Excess Weight
Lossa |
|---|
| At 2 years | At 10 years |
|---|
| Roux-en-Y gastric bypass (RYGB) | Higher BMI, GERD, diabetes | 55% to 75% | 52% to 69% |
| Sleeve gastrectomy | Metabolic disease | 50% to 70% | 67% to 71% |
| Laparoscopic adjustable gastric banding (LAGB) | Lower BMI, no metabolic disease | 30% to 50% | 38% to 47% |
| Biliopancreatic diversion with duodenal switch (BPD/DS) | Super-obesity (BMI ≥50), diabetes | 63% to 80+% | 68% |
| Single anastomosis duodenal-ileal bypass with sleeve (SADI-S) | Super-obesity | 74% | NA |
| One-anastomosis gastric bypass (OAGB) | Higher BMI, diabetes | 68% to 80% | 73% |
| BMI = body mass index, GERD = gastroesophageal reflux disease, NA = not
available. | | aMean average |
|
22 . Which of the following statements regarding indications for MBS is TRUE?
| A) | | Patients older than 70 years of age should not be offered MBS. |
| B) | | MBS is recommended for patients with BMI of 40 only in those with at least one obesity-related complication. |
| C) | | A BMI >25 suggests clinical obesity in Asian patients, and those with BMI >27.5 should be offered MBS. |
| D) | | MBS should be considered in patients with BMI 25–30 who do not achieve substantial or durable weight loss. |
BARIATRIC SURGICAL PROCEDURES AND DEVICES
The universally applied threshold for bariatric surgery
(i.e., BMI >40 or BMI >35 with comorbidities) was set in 1991 by the National
Institutes of Health. With significant advances in obesity science and safer, more effective
bariatric approaches supported by three decades of evidence, this indication no longer
reflects best practice and was replaced with new practice guidelines by the ASMBS in 2022
[126]. According to the ASMBS, MBS is
recommended for [126]:
Patients with BMI ≥35, regardless of presence, absence, or severity of
obesity-related complication
Patients with type 2 diabetes and BMI ≥30
The BMI thresholds should be adjusted in Asian
populations [126]. A BMI >25 suggests
clinical obesity in these patients, and those with BMI >27.5 should be offered MBS.
The ABMS asserts that there is no upper age limit to MBS
[126]. Older patients who could benefit
from MBS should be considered after careful assessment of comorbidities and frailty.
MBS is also an effective treatment of clinically severe
obesity in patients who need other specialty surgery, such as joint arthroplasty, abdominal
wall hernia repair, or organ transplantation. Severe obesity is a chronic disease requiring
long-term management after primary MBS, which may include revisional surgery or adjuvant
antiobesity medication to achieve or sustain desired treatment effects [126].
23 . What should MBS candidates and patients be counseled regarding tobacco use?
| A) | | Tobacco use, and cigarette smoking in particular, must be avoided at all times by all patients. |
| B) | | Patients who smoke cigarettes should stop as early as possible, preferably one year but at the very least six weeks before MBS. |
| C) | | Tobacco use should be avoided post-MBS given the increased risk of poor wound healing, anastomotic ulcer, and overall impaired health. |
| D) | | All of the above |
BARIATRIC SURGICAL PROCEDURES AND DEVICES
Tobacco use, and cigarette smoking in particular, must
be avoided at all times by all patients. Patients who smoke cigarettes should stop as
early as possible, preferably one year but at the very least six weeks before MBS. In
addition, tobacco use must be avoided post-MBS given the increased risk of poor wound
healing, anastomotic ulcer, and overall impaired health. Structured intensive smoking
cessation programs are preferable to general advice and should be implemented [125].
24 . All of the following intragastric balloon devices are ASMBS-endorsed and FDA-approved for six-month dwell-time, EXCEPT:
| A) | | Orbera |
| B) | | Obalon |
| C) | | ReShape Duo |
| D) | | TransPyloric Shuttle |
BARIATRIC SURGICAL PROCEDURES AND DEVICES
Three intragastric balloon devices are ASMBS-endorsed
and FDA-approved for six-month dwell-time. The Orbera and Reshape balloons are both filled
with methylene blue and saline. A leak or rupture releases the dye, which turns the urine
blue to rapidly reveal the problem [135,228].
Contraindications to intragastric balloon devices use
include prior abdominal or weight-reduction surgery, inflammatory bowel disease,
obstructive disorders, GI ulcers, severe reflux, prior GI bleeding, severe liver disease,
coagulopathy, ongoing alcohol use disorder, or intestinal varices, stricture, or stenosis
[239,245].
Orbera, the most widely and longest used intragastric
balloon device, is an endoscopically inserted single gastric balloon filled with 400–750
mL of fluid [245]. In a meta-analysis of
1,683 patients, weight loss at 6 and 12 months was 13.2% and 11.3%, respectively. Common
adverse events were pain (34%), nausea (29%), GERD (18%), gastric mucosal erosion (12%),
and balloon removal due to intolerability (7.5%). Severe events included gastric ulcers
(2.0%), balloon displacement (1.4%), small bowel obstruction (0.3%), perforation (0.1%),
and death (0.08%). All perforations occurred in patients with prior gastric surgery; all
deaths were secondary to perforation or aspiration. Thus, individualized, detailed risk
assessment is necessary for patients planning to undergo intragastric balloon device
placement [228]. Orbera early removal is
also associated with use of selective serotonin or serotonin-norepinephrine reuptake
inhibitors (SSRIs/SNRIs) [125].
Obalon uses up to three deflated balloons, swallowed as
capsules. Gas is then injected into the balloons under x-ray observation. Weight loss
typically is about 6.6%. In a registry of 1,343 patients, weight loss was 10.0% in the
indicated BMI category (BMI 30–40), 10.3% in BMI 25–30, and 9.3% in BMI >40. Adverse
event (14%) and severe adverse event (0.15%) rates included seven balloon deflations, none
of which resulted in obstruction [246].
Common adverse effects are mainly nausea and mild
abdominal pain, and serious events are rare. However, leaking occurs more easily with
gas-filled than liquid-filled balloons, and leaking balloons must be removed by
gastroscopy, a disadvantage with Obalon [228,245].
With the ReShape Duo balloon device, two balloons are
connected by a soft silicone rod. Each balloon is filled with 450 mL of fluid. The
two-balloon design is intended to prevent premature failure, better conform to the stomach
curvature, and improve patient tolerability. The ReShape device significantly reduces
severe adverse effects rates compared with Orbera, but postoperative adverse event rates
remain relatively high [228]. Average
weight loss is approximately 6.8% [135].
25 . Brown adipose tissue
| A) | | comprises 15% to 25% of body fat. |
| B) | | has more mitochondria (thus its brown appearance). |
| C) | | includes subcutaneous adipose tissue and visceral (abdominal) adipose tissue. |
| D) | | is absent in neonates but increases in adults and increases further in obese adults. |
APPENDIX: PHYSIOLOGY AND PATHOPHYSIOLOGY
Part of understanding obesity as a disease is
recognizing that adipocytes and adipose tissue have vital functions beyond energy storage
alone [128]. Adipose tissue is mostly
comprised of adipocytes, regulates multiple body processes critical to energy and
metabolic homeostasis, and is functionally classified into two types: white and brown
[128,285]. White adipose tissue is an active endocrine and immune organ that
includes subcutaneous adipose tissue and visceral (abdominal) adipose tissue and primarily
stores energy. However, subcutaneous adipose tissue contains brown-like inducible
adipocytes that perform mitochondrial and thermogenic functions and burn fat [286].
Brown adipose tissue, comprising 1% to 2% of body fat,
has more mitochondria (thus its brown appearance) and is abundant in neonates but
decreases in adults and decreases further in obese adults [286]. Brown adipose tissue produces heat
energy, termed thermogenesis, uponβ-adrenergic stimulation [287].
