Sleep deprivation may result in people consuming additional calories the following day, according to a systematic review and meta-analysis study led by researchers at King’s College London. The new study combined the results of 11 previous small intervention studies involving a total of 172 participants, to produce a more robust finding. Analysis included studies that compared a partial sleep restriction intervention with an unrestricted sleep control and measured energy intake over the following 24 hours.
The researchers also found there was a small shift in what sleep deprived people ate as they had proportionately higher fat and lower protein intakes, but no change in carbohydrate intake.If long-term sleep deprivation continues to result in an increased calorie intake of this size, it could contribute to weight gain.
The amount of sleep restriction varied between the studies, with the sleep deprived participants sleeping between three and a half and five and a half hours in the night. The control subjects spent between seven and 12 hours in bed.
Accumulating evidence that lack of sleep adds to weight gain
Dr Gerda Pot, senior author from the Diabetes & Nutritional Sciences Division at King’s College London and the Vrije Universiteit Amsterdam, 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’.
A previous small study in 26 adults found partial sleep deprivation resulted in greater activation of areas in the brain associated with reward when people were exposed to food. A greater motivation to seek food could be an explanation for the increased food intake seen in sleep deprived people in this study, the authors suggest. Other possible explanations include a disruption of the internal body clock affecting the body’s regulation of leptin (the ‘satiety’ hormone) and ghrelin (the ‘hunger’ hormone).
‘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,’ Dr Gerda Pot continued.
Haya Al Khatib, lead author and PhD candidate at King’s College London, said: ‘Our results highlight sleep as a potential third factor, in addition to diet and exercise, to target weight gain more effectively. We are currently conducting a randomised controlled trial in habitually short sleepers to explore the effects of sleep extension on indicators of weight gain.’
The authors of the study suggest that more intervention studies are needed into the effect of increased sleep duration over longer periods in everyday life on weight gain and obesity, as most of the studies included in this analysis were in controlled laboratory conditions over periods of one day to two weeks.