Obesity

Obesity is a chronic disease of excess body fat. Adults: BMI ≥30 kg/m². Children/adolescents: BMI-for-age ≥95th percentile (adjusted for age/sex).

• Obesity is very common and has serious health impacts. Over 40% of U.S. adults have obesity. It greatly raises risk for type 2 diabetes, hypertension, heart disease, fatty liver, and certain cancers, contributing to huge healthcare costs (~$173 billion in US). Childhood obesity often continues into adulthood, multiplying lifetime health risks.

• Adults often are asymptomatic aside from weight gain; frequently found on exam or during evaluation of comorbidities. Look for central obesity (high waist circumference), acanthosis nigricans (insulin resistance), striae, skin tags. Many patients have type 2 diabetes, dyslipidemia, fatty liver (elevated ALT), osteoarthritis, or symptoms of sleep apnea (snoring, daytime sleepiness).
• Children/adolescents often come for preventive visits or school physicals. They will have a BMI crossing the 95th percentile on growth charts. Family history of obesity is common. Physical exam may show acanthosis nigricans and early puberty (girls). Psychosocial effects (low self-esteem) may be present.

1. Confirm obesity: calculate BMI (adults) or BMI-for-age percentile (children) using height and weight. Classify severity (BMI 30–34.9 = Class I, 35–39.9 = Class II, ≥40 = Class III).
2. History: assess diet (caloric intake), physical activity, sleep habits, family history of obesity/CV disease, and medications (e.g., steroids, antipsychotics) that cause weight gain.
3. Physical exam and labs: measure waist circumference and blood pressure. Look for acanthosis nigricans, striae, and signs of obesity complications. Screen blood tests: fasting glucose/HbA1c, lipid panel, liver function (ALT), and consider TSH/cortisol if endocrine causes suspected.
4. Evaluate for comorbidities and complications: sleep study for snoring, liver ultrasound for fatty liver, PCOS workup for females (androgens, ultrasound), and mental health screening if needed.
5. Determine treatment plan: emphasize lifestyle interventions and set realistic goals. Assess readiness to change.
6. If BMI is very high or comorbidities severe, consider referral to a weight management program, dietitian, or endocrinologist.

1. Lifestyle (first-line): calorie-restricted diet, increased physical activity (e.g. ≥150 min moderate exercise/week for adults), and behavioral counseling or structured weight-loss program.
2. Pharmacotherapy (adults): for BMI ≥30 or ≥27 with comorbidity. Options include GLP-1 agonists (e.g. liraglutide, semaglutide), naltrexone–bupropion, orlistat, phentermine–topiramate, and short-term phentermine.
3. Pharmacotherapy (children ≥12): consider after lifestyle modifications. Options include orlistat, metformin (for insulin resistance), and GLP-1 agonists (liraglutide, semaglutide) with pediatric endocrinology guidance.
4. Surgery: Bariatric procedures (gastric bypass, sleeve gastrectomy) if BMI ≥40, or ≥35 with severe comorbidity (diabetes, sleep apnea). Adolescents (≥13y) with BMI ≥35 and failed medical therapy may be referred for surgical evaluation.

• BMI categories: underweight <18.5, normal 18.5–24.9, overweight 25–29.9, obese I 30–34.9, II 35–39.9, III ≥40 (morbid obesity).
• In children: overweight = 85–94th percentile, obesity ≥95th percentile on growth charts.
• Body habitus: "Apple" (android/central) obesity has higher metabolic risk than "pear" (gynoid) obesity.
• Recall BMI formula: weight (kg) divided by height (m) squared.

• Early-onset obesity (infancy/early childhood) or failure to thrive with obesity (short stature, delayed bone age): suggests endocrine/genetic cause (hypothyroidism, Cushing, Prader-Willi).
• Rapid unexplained weight gain with striae, moon facies, or proximal weakness: consider Cushing syndrome.
• Severe obesity in a child with family history of non-obesity or coexisting short stature: evaluate for endocrine disease.
• Obesity with unusual comorbidities (e.g. polycystic ovary syndrome in a young girl, nonalcoholic steatohepatitis, pseudotumor cerebri): screen and manage early.

1. Measure BMI (or BMI percentile) at routine visits to identify obesity.
2. Gather history: dietary intake, activity level, family history of obesity/diabetes, and review medications.
3. Perform exam and basic screening tests: check blood pressure, look for acanthosis nigricans, and order glucose (HbA1c), lipids, and liver enzymes. Obtain endocrine labs (TSH, cortisol) if indicated.
4. Initiate intensive lifestyle counseling: set achievable diet and exercise goals with patient/family.
5. Re-evaluate progress after 3–6 months: if no improvement or comorbidities persist, escalate to pharmacotherapy or structured weight management programs.
6. Refer as needed: for BMI ≥40 (or ≥35 with complications) consider bariatric surgery evaluation, and involve dietitians, endocrinologists, or pediatric obesity clinics for support.

• Middle-aged patient (BMI 38) with type 2 diabetes, hypertension, and dyslipidemia → classic metabolic syndrome due to obesity.
• Teenage girl (BMI >97th percentile) with irregular menstruation and hirsutism → suggestive of obesity-associated PCOS (insulin resistance).
• Obese patient reporting loud snoring, daytime fatigue, and morning headaches → consider obesity hypoventilation syndrome/obstructive sleep apnea.