Twelve weeks of time-restricted eating (8–10 hour window) does not result in significantly greater weight loss or improvements in metabolic flexibility, glycemic control, or body composition compared to caloric restriction or unrestricted eating in obese adults without diabetes.

When a person eats fewer calories than they burn, their body uses stored fat for energy, which leads to weight loss. Whether they eat those calories in a short window or spread out over the day, the total amount of energy used and stored stays the same. The body adjusts how it uses fuel based on total calories, not when they are eaten, so metabolic flexibility, blood sugar control, and body composition change only if the total energy intake changes.