Energy balance

Long-term weight loss triggers a proportional increase in appetite (energy intake) of approximately 100 kcal/day per kilogram of lost weight, which is the primary driver of weight regain and exceeds metabolic adaptation effects.

When you lose weight, your body biologically fights back by increasing your appetite by roughly 100 calories per day for every kilogram lost. This is a stronger force than your metabolism slowing down. If you stop actively managing your food intake, your appetite will naturally drive you back to your pre-weight-loss eating habits, causing regain. Successful long-term maintenance requires recognizing this biological pressure and maintaining vigilant behavioral strategies to resist the increased hunger, as self-reported 'diet adherence' often masks the fact that actual intake has returned to baseline.