Lack of sleep means ‘you’ll gorge on an extra 400 calories a day – that’s the equivalent of 3 STONE a year’

PEOPLE are more likely to binge on junk food after a bad night’s sleep, a study found.

Adults consumed an additional 385 calories – the equivalent of one and a half Mars Bars – on days after they were deprived of kip.

They also swapped healthy foods, high in protein, for unhealthy items full of fat.

But researchers from King’s College London found physical activity levels remained unchanged – meaning the extra calories were not burned off.

Consuming an additional 385 calories a day could lead to 3.3lbs of weight gain after just one month or three stone over the course of a year.

Scientists combined the results of 11 previous studies that analysed the sleep, exercise and eating habits of 172 participants.

The amount of sleep varied between the studies, with the deprived participants sleeping between three-and-a -half and five-and-a-half-hours at night.

The other group spent between seven and 12 hours in bed.

If long-term sleep deprivation continues to result in an increased calorie intake of this magnitude, it may contribute to weight gain

Dr Gerda Pot, Kings College London

Researcher Dr Gerda Pot, from KCL, said: “The main cause of obesity is an imbalance between calorie intake and expenditure and this study adds to accumulating evidence that sleep deprivation could contribute to this imbalance.

“So there may be some truth in the saying ‘Early to bed, early to rise, makes a man healthy and wise'.

“This study found that partial sleep deprivation resulted in a large net increased energy intake of 385 kcals per day.

“If long-term sleep deprivation continues to result in an increased calorie intake of this magnitude, it may contribute to weight gain.

“Reduced sleep is one of the most common and potentially modifiable health risks in today’s society in which chronic sleep loss is becoming more common.

“More research is needed to investigate the importance of long-term, partial sleep deprivation as a risk factor for obesity and whether sleep extension could play a role in obesity prevention.”

Haya Al Khatib, who also worked on the study, said: “Our results highlight sleep as a potential third factor, in addition to diet and exercise, to target weight gain more effectively.”

Sleep deprivation is thought to result in greater activation of areas in the brain associated with reward when people are exposed to food.

And experts say disruption of the internal body clock may affect the body’s regulation of ‘satiety’ hormone leptin and ‘hunger’ hormone ghrelin.

The study is published in the European Journal of Clinical Nutrition.