Behavior and metabolism: Lack of sleep as a fattening agent

Behavior and metabolism

Numerous studies show that people who don't get enough sleep have an increased risk of obesity. Evidence-based research demonstrates why this is the case. Regardless of weight gain, the risk of diabetes also increases.

The first years of having a child are often characterized by interrupted nighttime sleep. Sleep deprivation can alter eating habits and metabolism and promote weight gain. / © Getty Images/Artfoliophoto

According to data from the Robert Koch Institute, one in two adults in Germany is overweight (defined as a BMI ≥25 kg/m²), and about one in five of these adults suffers from obesity (BMI ≥30 kg/m²). But it's not just the scale that's causing concern: Only around half of adults sleep the recommended 7 to 9 hours on weekdays (chart). On weekends, the figure rises to about 60 percent.

Sleep deprivation is a growing problem: Epidemiological studies show that insufficient sleep poses a major challenge, especially for people who want to maintain a healthy weight. A 2020 review of around 155,000 participants from twelve studies shows that short sleepers have a 1.4-fold increased risk of developing obesity later in life (1).

Sleep durations recommended by the National Sleep Foundation (a non-profit organization based in the USA) according to age / © PZ/Stephan Spitzer

However, the link between insufficient sleep and weight doesn't only affect adults: A 2021 analysis of 33 studies involving nearly 58,000 children and adolescents shows that even among the youngest children, insufficient sleep increases the risk of overweight and obesity. The shorter the sleep, the greater the risk – this applies to toddlers from one year of age as well as school-age children. In contrast, longer sleep has a protective effect against obesity (2).

These correlations across all age groups highlight the importance of healthy sleep as a key factor in the prevention of overweight and obesity. Given the increasing incidence, this issue is becoming increasingly important not only for individual health but also for public health.

Those affected by this disorder, from a variety of life situations—from parents with restless toddlers to night shift workers—often exhibit a noticeable craving for sweet and high-calorie foods. This phenomenon raises the question of the biological mechanisms behind the connection between sleep deprivation, eating behavior, and metabolic disorders.