Does Lack Of Sleep Make You Fat?

A study conducted previously and published in the American Journal of Clinical Nutrition by researchers Christian Benedict and Helgi Schiöth, of the Department of Neuroscience at Uppsala University, showed that a single night of total sleep loss in young normal weight men increased levels of hunger, which indicated that an acute lack of sleep may affect a person's food perception.

In a new study, the same researchers from Uppsala University, tried to isolate the part of the brain that was affected by acute sleep loss. They showed that a specific brain region that contributes to a person's appetite sensation is more activated in response to food images after one night of sleep loss than after one night of normal sleep. Poor sleep habits can therefore affect people's risk of becoming overweight in the long run.

Christian Benedict says, "After a night of total sleep loss, these males showed a high level of activation in an area of the brain that is involved in a desire to eat. Bearing in mind that insufficient sleep is a growing problem in modern society, our results may explain why poor sleep habits can affect people's risk to gain weight in the long run. It may therefore be important to sleep about eight hours every night to maintain a stable and healthy body weight."

This study only involved 12 normal weight men and it seems a bit of an extrapolation to conclude that this would be the case in everyone, male or female, overweight or of normal weight. What's more researchers compared the results after a night with normal sleep with those obtained after one night without sleep, not reduced sleep, so I'm not sure where they got the 8 hours sleep from...
However I do think that common sense dictates that when you haven't slept well, you are more susceptible to eating badly and thus gain weight if this happens regularly.