Not getting enough shut eye? It may be contributing to those extra pounds, according to a new study in the Journal of Nutrition.

Decades of research already suggest a link between chronic sleep deprivation and an increased risk of obesity, but this study investigated sleep duration and energy balance using objective measures of total energy intake and physical activity energy expenditure.

In the study, almost 230 participants self-reported sleep duration and researchers used doubly labelled water to determine energy intake and expenditure.

Researchers found that short sleep, 6 or fewer hours, was associated with a higher risk of obesity, but the relationship was not linear. In comparison to those who slept 6 hours or less, those who slept 8 hours had a 67% lower risk of obesity and participants who slept longer, for at least 9 hours per night had a 50% lower odds.

Those who sleep longer, compared to short sleepers, tend to eat fewer calories and expended less energy. Researchers found that participants who slept 9+ hours per night ate 187 fewer calories and expended 114 fewer calories than short sleepers.

Authors suggest longer sleep duration and better quality of sleep as one promising approach to weight management.