Cutting back on sleep increases levels of cortisol, a stress hormone, which causes fat storage. In a study of more than 6,000 participants, Japanese researchers found that shorter amounts of sleep were associated with higher BMI levels and larger waistlines in men. Sleep deprivation also interferes with recovery and growth hormone production.
Get at least seven hours of uninterrupted sleep every night. If you have trouble sleeping, stop drinking caffeine after mid-day, limit your alcohol consumption (which ruins sleep quality), and create a pre-bed ritual to get your body and mind ready for sleep.