Tired Brains Prefer Junk Food
by Mike Straus
It's something we've all experienced. Stayed up until 2 AM trying to finish that report for the boss. Skipped out on sleep to cram for finals. Tried coffee, Red Bull, even that ginseng stuff that cousin Frieda goes on about. And somewhere around that 48th consecutive hour of not sleeping, you empty out a vending machine, buy twelve double bacon cheeseburgers, and rig up a Pepsi IV.
A body of research is emerging that suggests sleep-related hunger is caused by hormones related to appetite – but the brain may have greater involvement than previously thought.
Two small studies presented in Boston have demonstrated that sleep deprivation increases activity in areas of the brain related to pleasure-seeking behaviour. Even worse, sleep deprivation may inhibit the parts of the brain related to self-control.
In one study, Columbia University researchers compared the brain activity of 25 participants following 8 hours of sleep one night and 4 hours of sleep the next. Researchers performed functional magnetic resonance imaging (fMRI) scans (which track blood flow in the brain) while participants were shown images of gut-rotting foods - like burgers and poutine - interspersed with images of healthy foods, such as fruits and oatmeal.
The parts of the brain associated with craving and reward were more active when participants were sleep-deprived than when they were well-rested, especially when they viewed images of unhealthy food.
The researchers suspect that tired people prefer high-calorie foods because their brains are looking for an extra energy boost to ride out the day.
“We think the restricted-sleep brain reacts to food stimuli as though it were food deprived,” says lead researcher Marie-Pierre St-Onge.
Several recent studies, including a different study led by St-Onge, have found that people who are sleep-deprived tend to consume more calories than those who are well rested.
Findings suggest, however, that hunger and cravings aren't the only reasons for this. Another study has found that brain functions that help us make complex choices – the so-called higher functions – are impaired by sleep deprivation. This study, at the University of California, showed that people have a stronger preference for unhealthy food when sleep-deprived than when well rested.
But the brain scans showed that the participants had not only more brain activity in the pleasure centre, but less activity in the decision-making centre. This suggests people who are sleep-deprived are drawn to high-calorie foods because their ability to process information and make decisions is impaired.
The key to a healthy lifestyle is making healthy choices, and that begins with having a properly functioning brain. So if you want to live a healthier life, start by catching a few extra Z's.
Your stomach will thank you.
Mike Straus has a Bachelor's degree in Psychology from the University of British Columbia.
He has been published in the Kelowna Capital News, the UBC Phoenix, and others.
His goal is to educate the public on how to use the power of psychology to live a healthier life.