Most people know they should cut calories and exercise more to trim down, but there’s now significant scientific evidence that another critical component to maintaining your natural normal weight  is avoiding sleep deprivation, sleep scientists say.

“There is no doubt that insufficient sleep promotes hunger and appetite, which can cause excessive food intake resulting in weight gain,” says Eve Van Cauter, director of the Sleep, Metabolism and Health . She has spent 15 years studying the topic.

Here are six specific ways sleep deprivation is linked to weight gain.

  1. When you are running on low energy, you automatically go for a bag of potato chips or other comfort foods.
  4. The more sleep-deprived you are, the higher your levels of the stress hormone cortisol, which increases your appetite.
  5. When you’re sleep deprived, the mitochondria in your cells that digest fuel start to shut down.