The study, carried out at the University of California, Berkeley, showed that people who suffered a sleepless night were more likely to reach for doughnuts or pizza than for good bodybuilding proteins, whole grains and leafy green vegetables.
The researchers examined the brain regions that control food choices and claim the findings shed new light on the link between poor sleep and obesity
Professor Matthew Walker, UC Berkeley professor of psychology and neuroscience, said:
“What we have discovered is that high-level brain regions required for complex judgements and decisions become blunted by a lack of sleep, while more primal brain structures that control motivation and desire are amplified.
“High calorie foods also became significantly more desirable when participants were sleep-deprived and this combination of altered brain activity and decision making may help explain why people who sleep less also tend to be overweight or obese.”
Previous studies have also linked poor sleep to a greater appetite for sweet and salty foods, but the latest findings provide a specific brain mechanism explaining why food choices change for the worse following a sleepless night.
Stephanie Greer, a doctoral student in Professor Walker's Sleep and Neuroimaging Laboratory, added: “These results shed light on how the brain becomes impaired by sleep deprivation, leading to the selection of more unhealthy foods and, ultimately, higher rates of obesity.”
In this newest study, researchers measured brain activity as participants viewed a series of 80 food images that ranged from high to low calorie and healthy and unhealthy, and rated their desire for each of the items.
As an incentive, they were given the food they most craved after the MRI scan.
Food choices presented in the experiment ranged from fruits and vegetables, such as strawberries, apples and carrots, to high calorie burgers, pizza and doughnuts.
On a positive note, Professor Walker said, the findings indicate that ‘getting enough sleep is one factor that can help promote weight control by priming the brain mechanisms governing appropriate food choices’.