Too little shut-eye can make your body store more fat Thomas Baker / Alamy Stock Photo

One sleepless night may be enough to make your body start storing extra fat and breaking down muscle, research suggests.

This helps to explain why people with insomnia and shift workers with disrupted sleep patterns are particularly prone to obesity and type 2 diabetes, says Jonathan Cedernaes at Uppsala University in Sweden. He and his colleagues took fat and muscle samples from 15 healthy young men on two separate mornings – one after a good night’s sleep and the other after they lay awake all night.

After the sleepless night, the participants’ muscles showed signs of protein breakdown. Their fat tissue, in contrast, had elevated levels of proteins and metabolites that are involved in promoting fat storage.


Staying awake all night also appeared to change the expression of several genes in fat tissue that are associated with obesity and type 2 diabetes. These findings fit with previous research showing that sleeping for just 4 hours per night for five consecutive nights can trigger weight gain.

Sleep restriction may mess with the body’s metabolism by disrupting normal hormonal cycles, says Cedernaes. Sleep loss appears to impair the production of hormones involved in muscle maintenance – like growth hormone and testosterone – and to increase morning levels of cortisol, which promotes fat storage, he says.

The researchers are now investigating whether specific diet or exercise plans could be used to counteract these effects. “It may be the case, for example, that eating protein-rich foods or doing resistance training might reduce the risk of muscle degradation,” says Cedernaes.

Journal reference: Science Advances, DOI: 10.1126/sciadv.aar8590