"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," said first author Colin Chapman of Uppsala University in Sweden.
The research team recruited 14 healthy men to participate in two situations: stay awake for one night, then go grocery shopping the next morning, and secondly, sleep as usual and then go shopping.
Having only a fixed budget of 300 SEK (approximately $50), the men were instructed to purchase as much as they could out of a possible 40 items, including 20 junky foods and 20 healthier options. The prices of the fatty, high-caloric foods were then varied to determine if total sleep deprivation affects the flexibility of food purchasing. Before going shopping, the subjects consumed a normal breakfast. Findings showed that the tired men purchased significantly more calories and more food overall than they did after a night of normal sleep.
"Our findings provide a strong rationale for suggesting that patients with concerns regarding caloric intake and weight gain maintain a healthy, normal sleep schedule," said Chapman.
While the research shows the most extreme example of sleep deprivation, staying up all night, coming up a few hours short here and there could play a role in cutting into your resistance to fatty foods, a concept backed by previous research. In fact, a separate study announced last month from the University of California found evidence that a lack of sleep causes changes in brain activity that lead to people feeling hungrier and craving more fattening foods.