Hunger
- When you miss out on sleep, you eat more. If you're feeling tired and your biorhythms are out of sync, you have higher levels of the hormone ghrelin, writes trainer Jennifer Cohen of No Gym Required on the "Forbes" magazine website. Increased ghrelin production makes you crave sugar and junk foods, which aren't good for your waistline.
Cortisol
- Cortisol is another hormone, often known as the stress hormone. You do need some cortisol for regulating your metabolism, blood pressure and immune system, but too much can be detrimental. When you lack sleep, your body produces more cortisol than when you're well rested. Cortisol can directly affect fat gain, particularly around your stomach area, according to Christine Maglione-Garves and Dr. Len Kravitz of the University of New Mexico. Deep abdominal fat has four times more cortisol receptors than subcutaneous fat just below the skin, meaning that a high cortisol level could make you gain belly fat.
- Fat Loss vs. Weight Loss
- Calories aren't the only important factor in losing stomach fat. A study published in a 2010 edition of the "Annals of Internal Medicine" showed that sleep deprivation affects the amount of fat you lose. Participants were placed on a restricted calorie diet and allowed either seven and a half or eight and a half hours of sleep. Weight loss was similar between both groups, but the group sleeping more had a much higher percentage of fat loss, while the sleep-deprived group lost more fat-free mass. If you want to lose fat and preserve muscle, sleeping more is the answer.
Considerations
- While getting more sleep probably won't have much of a direct impact on stomach fat in particular, bar the cortisol connection, sleeping more could help you lose more total fat both directly and indirectly. Getting a few extra hours in bed each week can also give you more energy, resulting in higher motivation levels and an increased enthusiasm for training, meaning you'll work harder in the gym and burn more calories.
