Sleep should be a top priority. The average adult needs seven to eight hours of sleep each night. Sleep deficiency increases your risk of heart disease, diabetes, obesity, cancer and depression, the National Institutes of Health reports. Without the sleep you need, all efforts to take charge of your health lose some of their effectiveness. That's because sleep is what helps you recover from exercise, think clearly and manage stress. Sleep deprivation can undo all of your hard work with diet and exercise because a tired body can overproduce insulin and ghrelin (the "hunger" hormone). So set aside enough time or work on relaxing so you can catch solid Z's every night.