You always knew that lack of sleep was a bad thing, but did you know that it can make you fat?
This specific correlation has long been suspected, but a new study by researchers from the University of California recently published some evidence to back it up. Using MRI (magnetic resonance imaging) scans, Stephanie M. Greer, Andrea N. Goldstein and Matthew P. Walker were able to measure how the human brain reacts to various food choices when subjects are tired.
The team studied 23 participants who each had their brains scanned after a full night of sleep, then once again after being deprived of sleep. The scan then measured the brain activity of each subject as they rated the desirability of certain foods.
Without a normal night's sleep, researchers observed that participants experienced impaired activity in the parts of their brains where consequences are considered and satisfaction is determined. "An additionally interesting finding was that high calorie foods became more desirable to the sleep-deprived participants,'' Walker told AFP.
So not only is judgment impaired — concerning satisfaction and consequence — but fattier foods become more desirable. It's a phenomenon that Walker describes as a "double hit" to the brain.
Furthermore, when participants were tired, they requested foods containing about 600 calories more than those who got eight hours of sleep.
He also pointed out that participants reported the same levels of hunger whether they slept well or not. "That’s important because it suggests that the changes we’re seeing are caused by sleep deprivation itself, rather than simply being perhaps more metabolically impaired when you’re sleep deprived," he said.
"Our findings indicate that (to) regularly obtain sufficient amounts of sleep may be an important factor promoting weight control, achieved by priming the brain mechanisms governing appropriate food choices," Walker concluded.