Obesity
Adults. The goal is health, not weight alone.
Diagnose
- ObC Obesity Canada
| Decision | Guideline |
|---|---|
| Obesity | BMI over 30 defines obesity in adults. Obesity is a chronic disease. |
| Before drugs | Central adiposity (waist circumference, waist-to-hip or waist-to-height, sex- and ethnicity-specific cut-offs) with ethnicity-specific BMI and complications. |
Investigate
- ObC Obesity Canada
| Decision | Guideline |
|---|---|
| Approach | 5As: ask permission and readiness first. Then assess, advise, agree, assist. |
| Measure | Height, weight, BMI in all adults.Waist circumference if BMI 25-35. |
| Labs | BP in both arms, FPG or A1C, lipids.ALT where appropriate. |
| History and stage | Root causes, complications, barriers.Consider the Edmonton Obesity Staging System. |
Treat
- ObC Obesity Canada
| Decision | Guideline |
|---|---|
| Who | BMI 30 or more, or 27 or more with complications.Always with health behaviour change. Obesity Canada 2025 opens in a new tabCMAJ 2025 opens in a new tabCMAJ 2025, French opens in a new tab |
| Approved drugs | Six in Canada:Liraglutide, Naltrexone/Bupropion, Orlistat, Semaglutide, Tirzepatide, Setmelanotide. Long term when effective. |
| Do not | Compounded or unapproved products for weight loss. |
| ASCVD | Semaglutide 2.4 mg if BMI 27 or more, to reduce MACE. |
| HFpEF | Tirzepatide 15 mg if BMI 30 or more: CV death or worsening HF.Semaglutide 2.4 mg or Tirzepatide 15 mg for symptoms. |
| Sleep apnea | Tirzepatide 10 or 15 mg if moderate to severe and BMI 30 or more, with or without PAP. Liraglutide 3 mg if unwilling or unable to use PAP. |
| Bariatric surgery | BMI 40 or more, or 35 or more with a complication: consider. |
| Surgery, type 2 diabetes | BMI 30-35 with poorly controlled diabetes despite optimal care: consider. |
| Procedure | Sleeve, bypass or duodenal switch, with an experienced team. Adjustable banding: suggest not offering. |
| Drug | Dose | How often | BMI |
|---|---|---|---|
| Semaglutide | 2.4 mg SC | 1×/sem | 27 or more |
| Tirzepatide | 5, 10 or 15 mg SC | 1×/sem | 27 or more |
| Liraglutide | 3 mg SC | DIE | 27 or more |
| Naltrexone/Bupropion | 16 mg/180 mg PO | BID | 27-45 |
| Orlistat | 120 mg PO | TID | 28-47 |
Reviewed 18 October 2026 against the official sources below.
Sources
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