Macro partitioning

Orlistat reduces body weight by inhibiting gastric and pancreatic lipases, thereby reducing the absorption of dietary fats, with efficacy demonstrated in obese patients.

Orlistat helps you lose weight by blocking the absorption of about 30% of the fat you eat. You take it with meals, but you must keep your fat intake low (less than 30% of calories) to avoid unpleasant gastrointestinal side effects. It is effective for weight loss, especially when combined with a hypocaloric diet, but may be less effective than newer GLP-1 drugs.