when you are just chilling, the cells become dull, they don’t want anything (they’re in no mood to absorb nutrients and see no reason to make energy demands); so if you load your stomach at this time, it just gets converted to fat. But post activity (mental or physical) the cells are energy and nutrient deprived. This increases their sensitivity, which means that whatever you eat will get used up to replenish those hungry cells and not get converted to fat.
