In adults with obesity and prediabetes, 14 weeks of caloric restriction targeting a 390 kcal/day deficit resulted in significantly greater weight loss (mean reduction of 2.8 kg) and a 6.5% reduction in the fat-to-lean mass ratio compared to treatment with liraglutide 1.8 mg/day.

When a person eats fewer calories, the body breaks down fat for energy more aggressively and stops storing fat, while also protecting muscle tissue from being broken down. This happens because insulin levels drop, which tells fat cells to release stored fat and tells the body to keep muscle intact. In contrast, a drug that reduces hunger doesn't lower insulin enough to trigger this same fat-burning and muscle-saving response.