Sleep deprivation causes one to derive greater pleasure in eating unhealthy food while also increasing one’s appetite, says a new study published in the journal SLEEP. So, if you want to lose weight, and you are one prone to sleep deprivation, you know what to do – sleep more!
Numerous studies have shown that sleep deprivation is detrimental to the health, and unhealthy eating habits are often mentioned as part of the negative consequences. Sleep restriction is now increasingly being linked with weight gain in our contemporary societies: people are getting less and less sleeping hours as the obesity trend is spiralling. A new study shows how the process thereof is initiated by a chemical whose levels increase significantly during extra hours of wakefulness causing greater appetite and pleasure from eating high-fat snack foods.
The researchers analysed the behaviour of sleep-derived participants who were all otherwise young and healthy. They found that the volunteers could not resist “highly palatable, rewarding snacks” such as cookies, candy, and chips. This was the case even when they had already had a meal catering for 90% of their daily calorie needs only 2 hours before.
Another finding is that the effects on appetite were strongest at two times of the day: in the later afternoon, and early evening. It is to be noted that other studies have previously linked these two particular times with weight gain.
What causes this irresistible ‘need’ for junk food? Apparently, lack of sleep triggers the endocannabinoid 2-arachidonoylglycerol (2-AG) signal that, in turn, increases the pleasure and satisfaction involved in eating, says one of the authors, Erin Hanlon. This desire for food is the result of the enhancement of the endocannabinoid system which is also the target of marijuana.
The levels of 2-AG of the participants were found to be particularly high during the evening — that was the time when the individuals reported greater hunger and stronger desire for food. Normally, the 2-AG levels undergo a gradual increase during the day, and peak in early afternoon, at around 12:30 p.m, to ultimately go down at night.
Also, the participants would eat almost two times more fat when they were sleep-deprived than when they had an 8-hour sleep.
On the other hand, the energy costs of being awake for more hours appear to be minimal. According to the results of another study, the 4 extra hours of wakefulness would require around 70 more calories. However, the participants of the new study were consuming over 300 extra calories — this is what might ultimately cause significant weight gain.
Hanlon explains that their results basically imply that sufficient sleep will allow for greater control on one’s natural response if, for instance, one has a Snickers bar handy while sleep deprivation will boost one’s hedonic drive such that resisting will be less likely to happen.
The authors conclude that the 2-AG might constitute a mechanism through which sleep loss causes excessive food intake in spite of the only modestly-greater energy needs. Furthermore, sleep restriction is not only seemingly linked with increased caloric intake, but also with modifications in the hedonic features of eating.