Hunger Hormones and Sleep: Why You Crave Sweets After a Short Night

Two nights of four hours: ghrelin goes up, leptin goes down, and hunger and cravings for sweet, salty, and starchy foods are a quarter higher. One week of five hours in healthy young people: insulin sensitivity falls by 25%, as in prediabetes. Sleep-deprived people with free access to food eat 300-500 kcal more and do not notice. The sleep-deprived brain: the reward area is more active in response to food, while the frontal cortex — responsible for control — is quieter. It is literally a different brain looking at a pastry.

The sleep-deprived brain looks for the fastest energy — sugar. Plus, cortisol is higher in the morning and does not fall in the evening: it raises blood sugar from the reserves, and then the body demands that it be replenished. Plus endocannabinoids — substances that increase with sleep deprivation and intensify the pleasure of eating, as after marijuana. Three mechanisms working in the same direction. Willpower is the last thing to blame here. About the circadian clock — circadian rhythms and meal timing.

A woman who sleeps 6 hours will “lose control” on any diet, and it is not about the method. Sleep is the condition that makes a fasting window manageable and allows cravings for sweets to disappear on their own instead of being “overcome.” If your weight is stuck despite a balanced plate, the first question is not “what should you remove from your diet?” but “how many hours do you sleep?” The stages and what happens in them — sleep stages and fat.