Sleep duration and quality affect the balance of two appetite-regulating hormones: leptin (which signals satiation/fullness) and ghrelin (which signals hunger). Insufficient sleep shifts this balance toward increased hunger signaling and reduced satiety, and is linked in practice to increased cravings for carbohydrate-heavy and generally unhealthy foods.
Practical implication: sleep is framed as a lever for weight-management goals in its own right, independent of diet or exercise interventions — poor sleep can undermine otherwise sound nutrition efforts by working against them hormonally.
The craving effect is explained by two hormones moving in opposite, sleep-sensitive directions: leptin (signals satiation) drops with insufficient sleep, and ghrelin (signals hunger) rises — the combined imbalance drives cravings specifically toward carbohydrate-heavy foods rather than hunger in general. This gives sleep restriction a direct mechanistic link to weight management independent of activity level or willpower.