Why we can't resist that doughnut when we're sleep-deprived
Lack of sleep linked to more active reward centre in brain



11:03 GMT, 13 June 2012

A poor night's sleep leaves you far more vulnerable to temptation, researchers say.

Those who fail to get enough shut-eye are more likely to opt for sweet treats like doughnuts and also gain more pleasure from them as well.

A team from Columbia University in New York found the brain's reward centre was more likely to light up in a study participant who was looking at unhealthy food if they were sleep deprived.

Oops! Skimping on sleep puts you at risk of succumbing to unhealthy treats

Oops! Skimping on sleep puts you at greater risk of succumbing to unhealthy treats

Study leader Dr Marie-Pierre St-Onge said: 'The same brain regions activated when
unhealthy foods were presented were not involved when we presented
healthy foods.

'The unhealthy food response was a neuronal pattern
specific to restricted sleep. This may suggest greater propensity to
succumb to unhealthy foods when one is sleep restricted.'

The researchers performed functional magnetic resonance imaging (fMRI) on 25 men and women of normal weights while they looked at images of healthy foods such as fruits and vegetables and unhealthy foods like pizza, doughnuts and sweets.

The scans were taken after five nights in which sleep was either restricted to four hours or allowed to continue up to nine hours, then the results were compared.

Previous research has shown that restricted sleep leads to increased food consumption in healthy people, and that a self-reported desire for sweet and salty food increases after a period of sleep deprivation.

Dr St-Onge said the new study's results provide additional support for a role of short sleep in appetite-modulation and obesity.

'The results suggest that, under restricted sleep, individuals will find unhealthy foods highly salient and rewarding, which may lead to greater consumption of those foods,' she said.

'Indeed, food intake data from this same study showed that participants ate more overall and consumed more fat after a period of sleep restriction compared to regular sleep. The brain imaging data provided the neurocognitive basis for those results.'

Experts have suggested the link between poor sleep and eating more may have evolutionary origins. Human ancestors would have slept less during summer months when they needed to eat more to fatten up for the winter.