The real reason sleep deprivation has you craving junk food

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Didn't get much sleep last night and find yourself indulging in ALL the (unhealthy) snacks? You're not alone. But don't blame your tummy - it's your nose which has you reaching for the pizza.

A new study has shown that "food odours are elevated" when we're sleep deprived - helping to explain why we eat more and gain weight when we're not clocking enough Zs. 

Researchers from Northwestern University's Feinberg School of Medicine asked adults who were running on only four hours sleep to inhale a number of food odours such as potato chips and cinnamon rolls, as well as non-food smells, while undergoing fMRI brain scans. Their food consumption was also monitored by the study authors, reports Science News.

A few weeks later, no longer sleepy, the participants returned to the lab and completed the same task.

When the team analysed their results, they found that when sleep-deprived, the adults in the study showed greater brain activity in two areas involved in olfaction - the piriform cortex and the orbitofrontal cortex - in response to the food smells, than they did when they had a good night's sleep.

In other words, the brain was more sensitive to food smells when participants were exhausted. 

It suddenly makes sense why those delicious pastries and muffins smell so much more enticing after bub's been up all night.

The link between sleep-deprivation and weight gain is already well-established. Last year an analysis of 11 previous studies found that after a night of limited sleep (around four hours), on average, people consumed 358 more calories than those who slept for seven to 12 hours. The researchers noted that this is the equivalent of about four and a half slices of bread.

So take your super-powered Mombie nose to bed early tonight - or stock up on chips for tomorrow!