10/02/2026
A potential reason for weight gain is poor sleep. Sleep deprivation is typically considered obtaining less than 7 hours of sleep per night. There are numerous studies in the scientific literature that suggest that this has metabolic effects that predispose to weight gain.
Sleep restriction influences two important hormones, leptin and ghrelin, that regulate metabolism and energy expenditure. Leptin is released from adipose tissue (fat) and acts on receptors in the hypothalamus of the brain where it inhibits appetite and promotes satiety thus limiting food intake.
Ghrelin, however, is released from the stomach and pancreas and stimulates appetite. Circulating ghrelin levels fluctuate over the course of the day in relation to food intake.
Leptin is decreased with sleep deprivation, whereas ghrelin is increased. In a short-term study of 10 men, 2 days of sleep restriction was associated with an 18% reduction in the leptin and a 28% elevation in ghrelin. These changes were associated with increased hunger and appetite, especially for calorie-dense foods with high carbohydrate content.
Both the decrease in leptin and the increase in ghrelin seen with sleep deprivation could potentially increase food intake and contribute to weight gain. Considering that increased caloric intake has been shown to promote sleep, sleep deprivation may prompt overeating as a compensatory mechanism to regain lost sleep
In addition to biological associations, several authors have highlighted the potential for behavioural mechanisms between sleep deprivation and obesity. The most straightforward of these states that individuals who sleep less have more opportunities to consume calories. Hence, time restricted eating may be effective in these individuals. Short sleepers may also experience fatigue, which reduces the likelihood of engaging in physical activity which helps to manage a healthy body weight.