Sleep Deprivation May Make People Buy More Junk Food
A bad night's sleep may make people buy more unhealthy foods the next day, according to new research.
Swedish researchers found that participants purchased more food in a mock supermarket when they didn't get enough sleep the night before.
Researchers said that sleep deprivation also boosted levels of ghrelin, a hormone that increases hunger, the following morning. However, there was no link between individual ghrelin levels and food purchasing. Researchers said this may mean that other mechanisms, like impulsive decision-making, may be more responsible for increased purchasing.
Investigators wanted to see whether sleep deprivation impairs or changes an individual's food purchasing choices. Previous findings revealed that not getting enough sleep impairs higher-level thinking and increases hunger.
"We hypothesized that sleep deprivation's impact on hunger and decision making would make for the 'perfect storm' with regard to shopping and food purchasing-leaving individuals hungrier and less capable of employing self-control and higher-level decision-making processes to avoid making impulsive, calorie-driven purchases," first author Colin Chapman, MSc, of Uppsala University, said in a news release.
The study involved 14 healthy male participants. Researchers gave each of the men a budget of $50 to purchase as much items as they could out of a possible 40 items on the morning after one night of total sleep deprivation, as well as after one night of sleep. Researchers said participants were given a standardized breakfast before the task to minimize the effect of hunger on their purchases.
The items included 20 high-caloric foods and 20 low-calorie foods. The prices of the high-caloric foods were then varied to determine if total sleep deprivation affects the flexibility of food purchasing.
The findings revealed that sleep-deprived men bought significantly more calories and grams of food than they did after one night of sleep. The study also found that blood levels of ghrelin were higher after sleep deprivation. However, this increase did not correlate with food purchasing behavior.
"Our finding provides a strong rationale for suggesting that patients with concerns regarding caloric intake and weight gain maintain a healthy, normal sleep schedule," said Chapman.
Researchers said the next step is to see if partial sleep deprivation also affects food-purchasing behavior, and to see with sleep deprivation influences purchasing behavior in general.