When Lack of Sleep Begin to Cause Weight Gain

On average, we sleep less than seven hours per night during the week. Lack of sleep exposes us to various detrimental effects on the body, including overweight. Is a single short night enough to be affected? Two doctors answer.

In 50 years, we have lost between one and one and a half hours of sleep. This was revealed in March 2019 by the Public Health France barometer, published in their weekly epidemiological bulletin. In total, the French sleep less than seven hours per night (6 hours and 34 minutes on workdays). The situation is problematic, as we know that lack of sleep disrupts the body and has deleterious effects on health, particularly increasing the risk of hypertension, type 2 diabetes, and obesity. While the link between bad nights and overweight has already been demonstrated, when does it start to show on the scale? Is a single short night enough?

An Impact on Hormones

Lack of sleep is one of the sources of obesity in children and adults. The reason? Hormonal changes. The mechanism is simple: 'To resist the fasting of the night, the body produces leptin, the hormone of satiety. During the day, to keep us awake, the metabolism secretes ghrelin, the hormone that promotes hunger. Reducing our sleep time disrupts these mechanisms and then increases appetite,' explains Dr. Olivier Coste, a sleep doctor in Bordeaux. Disturbed nights also change behavior and dictate our food choices. 'After a good night's sleep, we tend to go for low-calorie foods, whereas sugar and fat are more appealing when we haven't slept enough,' adds the specialist. QED.

According to Joëlle Adrien, a neurobiologist and research director at the National Institute of Health and Medical Research (Inserm), the longer wakefulness period is also responsible for increased food intake, particularly snacking. 'By extending the wakefulness period, we increase the available time for eating, but not for physical activity because we are tired. We then enter a vicious circle,' warns the professional.

Two Bad Nights Are Enough

If you thought that sleeping six hours a night for a week had no effect on your body, researchers remind us that these disturbances are visible after just two bad nights. 'The body is disrupted in cases of acute deprivation, like during an all-nighter, but also in cases of chronic deprivation. A person who does not get enough sleep for a week will have difficulty regulating their appetite,' emphasizes Olivier Coste.

These effects settle in over the long term and are hard to recover from. 'Sleep deprivation is never recoverable and can cause, in addition to obesity, diabetes and hypertension,' points out Joëlle Adrien. In terms of consequences on the scale, nature is obviously unfair. Bad nights will have very little impact on the weight of some, while others will notice them quickly and struggle to remedy them.

Evaluate Your Lack of Sleep

To know if you are getting enough sleep, observe your wake-up times during the week and on days off. 'If there is more than a two-hour difference between the weekend and the week, it indicates a lack of sleep. During the week, if we have trouble waking up in the morning or feel like sleeping in the early afternoon, we are probably not getting enough sleep,' specifies Olivier Coste.