For many people, weight loss is a means to improve body composition. Anyone who has done any sort of energy restricted diet has felt the rebound effect after going back to your normal eating habits. These effects can be profound and even more difficult to get rid of. This idea of diet rebounding scares many into even worse eating habits and the mechanisms seem to be cloudy.
Thankfully Suppveristy sheds some light on the topic.
The article reviews different correlations between fat free mass, energy intake, resting energy expenditure and length of diet. The goal was to further understand what happens post intervention. Essentially what happens is prolonged periods of reduced intake down regulates resting energy expenditure. However this decreased intake is the driving force behind the fat loss, which may create a perfect storm for metabolic dysfunction going forward. What the studies found was there was a notable decrease in resting energy expenditure post diet intervention and there was even less of a correlation between intake and fat free mass (regardless of the change). Although less understood, the mechanism is theorized to be a "confusion" of the appetite/satiety axis, the body acts as if more body fat was lost than in reality thus solidifying the reduced energy expenditure and accompanied with increased appetite post diet, it creates an ideal situation to increase fat stores. The amount of fat lost and the amount of fat remaining plays a large role as adipocytes act as a hormonal glad that can impact this axis. These studies were done on the obese population which although does not give us a direct transfer of knowledge, much can be learned and inferred from understanding their mechanisms.
What this means to you? Think twice about choosing your modality of weight loss. Everything you do leaves an imprint on your body, good or bad. Unless weight loss is absolutely necessary, maintaining bodyweight while increasing body composition at a slow rate may combat this rebound effect. Starting yourself on the higher end of intake and being cautious about when and how much you cut calories will also put you in a better long term position for sustainable changes in body composition.
I highly recommend looking through the full article
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