CORTISOL

Exposure to high amounts of stress produces the hormone cortisol, which can cause muscle breakdown and a redistribution of fat to your gut. “High levels at night are one of the biggest causes of weight gain, especially belly fat,” says Friedman.

HACK IT Install a “phone bowl” in your bedroom – and keep it far away from your bed. That means no mindless scrolling in bed, and therefore no more sleep lost to the smartphone abyss. Another perk: a solid night of sleep is a natural stress-reliever.