“No question about it: Sleep is vital to every aspect of health, but it’s especially important in controlling weight,” says David Katz, MD, founding director of Yale University’s Yale-Griffin Prevention Research Center. “We tend to think of sleep as downtime, but a better sleep comparison would be spa treatment, physical therapy, rehab, and rejuvenation, all rolled into one.” MORE: 8 Natural Sleep Remedies Proven To Work Here’s why sleep is so slimming—and what happens to your weight when you don’t make sleep a priority. Getting more than 6 hours of shut-eye keeps your appetite in check… Regularly burning the candle at both ends? A new study published in The American Journal of Human Biology shows that getting fewer than 6 hours of sleep each night can impact appetite regulation. When researchers looked at brain images of study participants, they found that inadequate sleep alters the secretion of the hunger hormones ghrelin (the hormone that makes us hungry) and leptin (the hormone that lets us know when we’re full). The result? You feel hungrier and overeat—particularly on quick-energy foods that are high in sugar—which increases your risk for developing obesity, diabetes, high blood pressure and even heart disease. …and makes junk food look less tempting.The American Journal of Clinical NutritionScientific Reports A poor night’s sleep might create a weakness for high-calorie, low-nutrient foods, suggests a study published in . When study participants got just 4 hours of sleep, they were more likely to respond to food stimuli—the sight and smell of enticing foods like bacon and pastries—than when they slept for 9 hours. Other research, published in , is even more specific: Not only do we consume more food following a night of sleep deprivation, but we also we consume more fat. MORE: 10 Perfect Bedtime Snacks A 30-minute power nap reverses the health effects of poor sleep. Fall short on your 7 to 8 hours of sawing logs last night? Take a power nap. According to new research published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM), a 30-minute nap can reverse the hormonal impact of a poor night’s sleep, and that can help rein in hunger as well as relieve stress and bolster the immune system. Regularly cutting sleep short by even a half-hour adds pounds. We do it all the time—stay up a half-hour later to watch a show or set the alarm to go off 30 minutes early to tackle a project. A new study from the Weill Cornell Medical College in Qatar finds that losing as little as 30 minutes of sleep a day for one year can lead to a 72% increased risk of becoming obese and 39% increased risk of developing insulin resistance (which promotes the onset of type 2 diabetes). MORE: 20 Ways To Sleep Better Every Night