Lack of sleep has long been associated with overeating, a unhealthy diet, being overweight, and the attendant delights. A new study has revealed the mechanism of this process. Scientists have found that lack of sleep causes an increase in blood levels of chemicals that enhance the sense of pleasure from eating, especially from sweet, salty and fatty foods.
In the experiment, young healthy volunteers, deprived of sleep, could not resist the temptation, and together pounced on cookies, chips and sweets, despite the fact that two hours before the test they ate lunch from dishes containing 90% of the daily calorie requirement. Worse, the peak of growth caused by lack of appetite falls at the end of the day and evening, when excess food has the greatest effect on weight gain.
“We found that lack of sleep enhances the signal, which can stimulate the hedonic aspect of food consumption, the pleasure and satisfaction of eating, ” said Dr. Erin Hanlon, a researcher at the University of Chicago. ” Lack of sleep seems to stimulate the endocannabinoid system, the same one that responds to the active ingredients of marijuana, which enhances the desire for food.”
This signal that triggers the process of increased appetite formation is the endocannabionoid 2-arachidonoylglycerol (2-arachidonoylglycerol, 2-AG). During the night, the level of this substance in the blood is low, but gradually increases during the day, reaching a maximum immediately after noon.
In people deprived of sleep, the level of endocannabionoid is higher than usual, and its peak is shifted to a later time. This causes an increased feeling of hunger and a strong desire to eat something. If at this time a person has access to snacks, then he eats almost twice as much fat as when he gets enough sleep. In this way, the body of sleepy people seeks to compensate for the lack of sleep by the influx of energy from outside.
In fact, according to Erin Hanlon, the body’s energy costs for overcoming the effects of lack of sleep are modest enough, about 17 additional calories for every hour of lack of sleep. To compensate for the cost of “lack of sleep” 4 hours, the body needs about 70 calories. But increased appetite leads to the fact that a person eats significantly more, over 300 calories. Excess calories, as you know, are usually stored in the form of fat reserves.
Hanlon and her colleagues included 14 healthy men and women over the age of 20 years. Scientists studied their appetite and diet in two situations. The first 4 days, the volunteers slept an average of 7.5 hours, the next – 4.2 hours.
Along with measuring blood levels of ghrelin, leptin and endocannabionoid 2-AG, researchers interviewed subjects to find out how they describe their own feelings.
During the period of sleep restriction, the level of 2-AG in the blood of volunteers was one third higher than usual, and the peak value remained unchanged for a long period from 2 pm to 9 pm. At this time, the volunteers experienced a strong feeling of hunger, despite the fact that they ate as usual. According to their own estimates, they were able to eat much more than in the first 4-day study period.
Despite the fact that the study is not large-scale, its results clearly show that it is much more difficult for a sleepy person to overcome a feeling of hunger than someone who has fully slept. Those who want to get rid of extra pounds should consider this.