Research suggests that there’s a link between how much people sleep and how much they weigh.
In general, children and adults who get too little sleep tend to weigh more than those who get enough sleep.
Longitudinal research indicates that younger adults in particular with short sleep durations are most at risk for weight gain. Adults aged 32-49 with less than 5 hours sleep per night were twice as likely to be obese after nine years compared to those who got more than 7 hours per night.
Several studies have sought to examine the cause of weight gain due to sleep deprivation. Several possible ways that sleep deprivation could increase the chances of becoming obese include:
Fatigue: Sleep-deprived people may be too tired to exercise, decreasing the “calories burned” side of the weight-change equation.
Appetite changes: Lack of sleep disrupts the balance of key hormones that control appetite, so sleep-deprived people may be hungrier than those who get enough rest each night.
Brain changes: Sleep deprivation leads to poorer food choices. One study has shown that when sleep-deprived, individuals preferred food choices that were highest in calories, like desserts, chocolate and potato chips. The sleepier they felt, the more they wanted the calorie-rich foods. In fact, the foods they requested when they were sleep deprived added up to about 600 calories more than the foods that they wanted when they were well rested. At the same time, brain scans showed that on the morning after the subjects’ sleepless night, the heavily caloric foods produced intense activity in the amygdala, which helps regulate basic emotions as well as our desires for things like food and experiences. That was accompanied by sharply reduced responses in cortical areas of the frontal lobe that regulate decision-making, providing top down control of the amygdala and other primitive brain structures.
Patel, S.R., & Hu, F.B. (2008). Short sleep duration and weight gain: A systematic review. Obesity, 16(3). 643-53.