Poor Sleep Is a Major Risk Factor for Weight Gain and Obesity. Poor sleep has repeatedly been linked to a higher body mass index (BMI) and weight gain ( 2 ). People's sleep requirements vary, but, generally speaking, research has observed changes in weight when people get fewer than seven hours of sleep a night ( 3 ).

Does lack of sleep cause belly fat?

Scientists have known for years that sleep deprivation makes you tired and cranky and less able to think clearly. It also can make you fat because it increases levels of a hunger hormone and decreases levels of a fullness hormone, which could lead to overeating and weight gain.

Does lack of sleep cause lose weight?

Now, a study that features in the International Journal of Obesity has found a link between insufficient or disrupted sleep and another issue — weight loss. The results showed that overweight people who did not sleep well lost less weight than their peers who had no sleep problems.