People that are deprived of sleep for one night buy more food of higher calorie content the following day, according to new research.
The research, published in Obesity, assessed the effects of sleep deprivation on individual consumer food purchasing choices after previous research has shown that a lack of sleep can increase hunger levels and impair high-level thinking.
Led by Colin Chapman from Uppsala University, Sweden, the research team found that sleep-deprived men purchased significantly more calories (+9%) and grams (+18%) of food than they did after one night of good sleep. The researchers also measured blood levels of ghrelin, finding that the hormone's concentrations were higher after total sleep deprivation; however, this increase did not correlate with food purchasing behaviour.
"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 Chapman.
On the morning after one night of total sleep deprivation, as well as after one night of sleep, Chapman and his team gave 14 normal-weight men a fixed budget (approximately $50). The men were instructed to purchase as much as they could out of a possible 40 items, including 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, explained the researchers.
Before the task, participants received a standardised breakfast to minimise the effect of hunger on their purchases, they added.
The researchers found that people who were deprived of one night's sleep purchased more calories and grams of food in a mock supermarket setting on the following day.
Sleep deprivation also led to increased blood levels of ghrelin, a hormone that increases hunger, on the following morning; however, there was no correlation between individual ghrelin levels and food purchasing, suggesting that other mechanisms—such as impulsive decision making—may be more responsible for increased purchasing, the authors suggested.
"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.
He added that follow up studies are needed to address whether these sleep deprivation-induced changes in food purchasing behaviour also exist under partial sleep deprivation. The team also suggested that additional research could also look into sleep deprivation's potential impact on purchasing behaviour in general, as it may lead to impaired or impulsive purchasing in a variety of other contexts.
Published online ahead of print, doi: 10.1002/oby.20579
" Acute sleep deprivation increases food purchasing in men"
Authors: Colin D. Chapman, Emil K. Nilsson, Victor C. Nilsson, et al