Guides comprehensive obesity management with BMI tracking, lifestyle interventions, medication options, and surgical referral criteria. Use when managing weight, counseling on obesity, or evaluating bariatric surgery candidacy.
Guides comprehensive obesity management with BMI tracking, lifestyle interventions, medication options, and surgical referral criteria.
Obesity (BMI ≥30 kg/m²) affects 42.4% of U.S. adults and is a primary driver of type 2 diabetes, cardiovascular disease, obstructive sleep apnea, NAFLD, osteoarthritis, and at least 13 types of cancer. Despite its prevalence, obesity is under-diagnosed (BMI often not calculated), under-discussed (clinicians avoid the topic), and under-treated (fewer than 3% of eligible patients receive anti-obesity medications). The American Medical Association recognized obesity as a disease in 2013, and CMS covers intensive behavioral therapy (IBT) for Medicare beneficiaries.
The treatment landscape has transformed with GLP-1 receptor agonists and GIP/GLP-1 dual agonists demonstrating 15-25% total body weight loss in clinical trials—approaching surgical outcomes. This skill provides a structured framework for diagnosis, lifestyle intervention, pharmacotherapy, and surgical referral that aligns with the Endocrine Society, AGA, and AAP guidelines for evidence-based obesity management.
| BMI Category | Classification | Waist Circumference Risk |
|---|---|---|
| 18.5-24.9 | Normal weight | N/A |
| 25.0-29.9 | Overweight | ≥40 in (M) / ≥35 in (F) = elevated risk |
| 30.0-34.9 | Class I obesity | Comorbidity assessment required |
| 35.0-39.9 | Class II obesity | Pharmacotherapy indicated; surgical evaluation if comorbidities |
| ≥40.0 | Class III obesity (severe) | Pharmacotherapy + surgical referral recommended |
Edmonton Obesity Staging System (assesses functional impact):
Screen for secondary causes if clinical suspicion:
All patients with BMI ≥25 should receive structured lifestyle counseling:
Dietary approach (no single diet is superior; adherence predicts success):
Physical activity:
Behavioral strategies:
Target: 5-10% total body weight loss at 6 months. Even 3-5% loss produces clinically meaningful improvements in glycemia, triglycerides, and blood pressure.
Indicated when BMI ≥30, or BMI ≥27 with weight-related comorbidity, and lifestyle alone insufficient after 6 months:
| Agent | Mechanism | Expected Weight Loss | Key Considerations |
|---|---|---|---|
| Semaglutide 2.4mg SQ weekly (Wegovy) | GLP-1 RA | 15-17% TBW (STEP trials) | GI side effects; titrate over 16 weeks; contraindicated in MTC/MEN2 |
| Tirzepatide SQ weekly (Zepbound) | GIP/GLP-1 dual agonist | 20-25% TBW (SURMOUNT trials) | GI side effects; titrate per protocol; supply constraints |
| Liraglutide 3.0mg SQ daily (Saxenda) | GLP-1 RA | 5-8% TBW | Lower efficacy than semaglutide; daily injection |
| Phentermine-topiramate ER (Qsymia) | Sympathomimetic + anticonvulsant | 8-10% TBW | REMS program; avoid in pregnancy (teratogenic); CV risk with phentermine |
| Naltrexone-bupropion ER (Contrave) | Opioid antagonist + NDRI | 5-6% TBW | Cannot use with opioids; BP monitoring; seizure risk |
| Orlistat (Alli/Xenical) | Lipase inhibitor | 3-5% TBW | GI side effects (steatorrhea); low efficacy; OTC available |
Assessment at 12-16 weeks:
NIH/ASMBS indications:
| Procedure | Mechanism | Expected Weight Loss | Mortality Rate |
|---|---|---|---|
| Roux-en-Y gastric bypass (RYGB) | Restrictive + malabsorptive | 25-35% TBW at 2 years | 0.1-0.3% |
| Sleeve gastrectomy | Restrictive (80% stomach removed) | 20-25% TBW at 2 years | 0.1% |
| Adjustable gastric band | Restrictive (band) | 10-15% TBW (declining use) | 0.05% |
| Biliopancreatic diversion with DS | Primarily malabsorptive | 35-45% TBW | 0.5-1% |
Pre-surgical requirements (varies by payer):