A new study has found that skipping just one night of sleep leads to a shift in brain activity that increases the desire to consume more fat the following day. Researchers say the study offers more insight into the relationship between lack of sleep and risk of obesity.
The loss of sleep actually altered what’s known as the brain’s “salience network.” The salience network is a pathway in the brain thought to guide decision-making. Brain scan analysis revealed exactly how the network changed in response to sleep loss allowing researchers to accurately predict how much more fat an individual might consume following lack of sleep.
Subjects were asked to spend five consecutive days (including four nights) in a sleep laboratory. On the first night all of them got a full night of rest, amounting to nine hours of time spent in bed, after which brain scans were conducted to record normal network function following good sleep. Then, 34 of the participants were randomly selected to be in the “sleep deprived group” on the second night. This meant they were kept awake all night, while the remaining participants were allowed eight hours of sleep. Brain scans were then conducted again, after which all participants were allowed to move about, watch TV, read, play video and board games, and eat as much or as little as they wanted. Food was ordered from an available menu, and anything consumed was recorded.
Those in the sleep-deprived group consumed roughly 950 extra calories during the night they were forced to stay awake. Total calorie consumption was about the same among the sleep-deprived group during the day that followed their all-nighter as it was among those who had normal sleep. However, when calories were broken down by content, investigators found a big difference between the groups. Those who hadn’t slept consumed significantly more fat and less carbohydrates than those who had slept. The sleep-deprived group also showed markedly greater activity in terms of salience network function.
Scientists concluded that people who experience bouts of forced wakefulness – such as those in the military, truck drivers or medical personnel – may be prone to making more unhealthy food choices due to a related shift in brain activity. While the study only explored one night of sleep loss, it is likely that chronic partial sleep deprivation would affect the brain in a similar way. It certainly supports the link between sleep patterns and changes in food intake and subsequent obesity. Therefore, getting adequate sleep may be a key strategy in maintaining a healthy weight and diet.