Fat mass / fat-free mass depletion feedback signals are more effective
Lean people regain fat faster because their feedback signals in response to the depletion of both fat mass (i.e. adipostats) and fat-free mass (i.e. proteinstats) – through the modulation of energy intake and adaptive thermogenesis – are more effective than in individuals with overweight or obesity, thus resulting in a faster rate of fat recovery relative to recovery of lean tissue (i.e. preferential catch-up fat) [1], [2]
"In fact, it appears that lean people overshoot in terms of weight gain because the state of hyperphagia (in response to weight loss) appears to persist well beyond complete recovery of fat mass and interestingly until fat free mass is fully recovered (which may take months during which time fat gain continues)." [1]