10/18/2025
New studies are revealing that without enough sleep, your body converts food into fat, even on a good diet.
Poor sleep causes your body to convert food into fat through a combination of hormonal and metabolic changes. Specifically, it increases hunger hormones like ghrelin, decreases the fullness hormone leptin, elevates the stress hormone cortisol and causes insulin resistance, which makes your body less effective at processing blood sugar and leads to it being stored as fat instead of energy.
To elaborate, lack of sleep causes your body to produce more ghrelin (“hunger hormone”) and less leptin (the “satiety hormone”), making you feel hungrier and less full. Poor sleep also increases levels of the stress hormone cortisol, which signals the body to conserve energy and can increase fat storage.
Sleep deprivation also impairs your body’s response to insulin. After a few nights of poor sleep, your cells can become less sensitive to insulin, which means they have trouble processing blood sugar for energy and instead store it as fat.
Studies also show that people who are sleep-deprived lose less fat and more muscle compared to those who get adequate sleep, even when eating the same amount of calories.
PMID: 20921542
