Why we crave junk food after a sleepless night decoded

Researchers have figured out why people crave more calorie-dense, high-fat foods such as doughnuts, chocolate chip cookies, and potato chips after a sleepless night, and how to help thwart those unhealthy choices.

According to the study, published in the journal eLife, our nose -- or olfactory system -- is affected in two ways by sleep deprivation.

First, it goes into hyperdrive, sharpening the food odours for the brain so it can better differentiate between food and non-food odours.

Then there is a breakdown in the communication with other brain areas that receive food signals, and with that our decisions about what to eat change, the researchers said.

"When you're sleep deprived, these brain areas may not be getting enough information, and you're overcompensating by choosing food with a richer energy signal," said Thorsten Kahnt, an assistant professor at Northwestern University Feinberg School of Medicine in the US.

"But it may also be that these other areas fail to keep tabs on ...