Lack of Sleep Makes You Crave More Junk Food: Study

Having even one night without sleep leads people to view junk food more favourably, research suggests.  

(Photo: iStockphoto)

Yes, we all know adequate sleep is important. Being sleep deprived makes us grumpy, tired, and act like a sloth bear throughout the day.

Now, add to it the risk of obesity. Earlier studies have sufficiently shown that sleep loss is associated with increased risk of obesity by demonstrating correlations between sleep duration and change in body mass index or body fat percentage. They have also spoken about the possible impact it can have on hormone levels, and thus affecting how hungry people end up feeling.

A recent study, published in the Journal of Neuroscience, established a connection between lack of sleep and the tendency to view unhealthy snacks more favorably.

The Study

As reported by The Guardian, the researchers took blood samples from thirty-two lean, healthy men, assessed their hormones and how food rewards are processed by the brain. They were served the same food: pasta and veal, an apple and a strawberry yoghurt.

Some were then sent to bed with a sleep-tracking device and others were kept awake all night. Their hunger and appetite were analysed and 29 were tested for their blood sugar. After a game in which they were presented with pictures of 24 snack food items, they were again asked to rate how much they would be willing to pay for them.

The latest study suggests that hormones have little to do with the phenomenon and that the cause could be changes in the activity between regions of the brain involved in reward and regulation.

In fact, having even one night without sleep can lead to people view junk food more favourably.

The results showed that whether sleep-deprived or not, participants were similarly hungry in the morning, and had similar levels of most hormones and blood sugar.

However, when participants were sleep-deprived, they were willing to pay more for a food snack than when rested, and had higher levels in their blood of a substance called des–acyl ghrelin, which is related to the “hunger hormone” ghrelin, though its function is not clear.

According to Professor Jan Peters, co-author of the research from the University of Cologne,

Our data brings us a little closer to understanding the mechanism behind how sleep deprivation changes food valuation.

Peters said that what was driving the changes in activity in the amygdala (where food rewards are processed) and hypothalamus(which is involved in regulating consumption) was still unclear.

We know that changes in other neurotransmitters such as dopamine occur following sleep deprivation, so this might be another candidate.

Jan Peters