A bad night sleep makes us crave junk food as it sharpens our sense of smell, making us home in on greasy grub such as burgers, chips and doughnuts, a study has found.
Sleep deprivation increases hormones called endocannabinoids, which have been linked to the “munchies”. They make eating more enjoyable — but also increase desire for specific types of foods such as biscuits, cakes and chips.
Prof Thorsten Kahnt, who led the study at Chicago’s Northwestern University, said, “It might be worth taking a detour to avoid your local doughnut shop next time you catch a 6am flight.
“When you’re sleep deprived these brain areas may not be getting enough information. You’re overcompensating by choosing food with a richer energy signal.
“We put all this together and asked if changes in food intake after sleep deprivation are related to how the brain responds to food odours – and whether this is due to changes in endocannabinoids.”
In experiments 29 men and women aged 18 to 40 were divided into two groups – one getting a normal night’s sleep and then, four weeks later, only four hours while the experience was reversed for the others.
The day after each test they were handed a controlled menu for breakfast, lunch and dinner – and then also offered a buffet of snacks with Scientists measuring how much and what they ate.
Prof Kahnt said: “We found participants changed their food choices. After being sleep deprived, they ate food with higher energy density like doughnuts, chocolate chip cookies and potato chips.”
The findings could shed light on the obesity crisis.
