Food cravings increase with fatigue from lack of sleep.
The number of calories you need for energy each day depends on many factors, including activity level, weight and body composition. The amount of sleep you get can directly affect how many calories you burn, as well as help determine success or failure in your weight-management efforts. Although you typically burn more calories in active hours than sleeping ones, missing your rest can lead to weight gain because your body craves extra calories to compensate for the lack of energy.
Sleep and Calorie Burning
All else equal, you may burn more calories during your lower-sleep days because you expend more energy moving than you do at rest. In a study published by the journal "Proceedings of the National Academy of Sciences," researchers found that sleep-deprived subjects burned an average of five percent more calories than their well-rested counterparts. So if you normally burn 2,000 calories per day, you may need an additional 100 calories per day with a reduced sleep lifestyle, depending on how active you are during your waking hours.
Sleep and Calorie Intake
Despite the potential increase in calorie burning, lack of sleep is shown to increase body weight, according to "Scientific American." When your body is tired, it wants quick energy to help get you through your day - which means you're more likely to eat more food than you need. Research shows that poor sleep habits reduce levels of leptin, a hormone that signals fullness, and also increase levels of ghrelin, a hormone that causes hunger. This one-two punch can make it difficult to stick to a sensible diet plan without a good night's sleep.
If you're trading sleep for TV time rather than physical activities, you may actually need fewer calories than you would if you'd spent the time in slumber. Your body uses about half as much energy when watching TV than sleeping, according to nutritionist Dr. Madelyn Fernstrom, who reports that you burn about 25 calories per hour staring at the screen, but double that sleeping because your body is more active in this state.
Because needs vary, it's difficult to pin a precise number of necessary sleep hours onto any one individual. However, the National Sleep Foundation reports that seven to eight hours of sleep per night is healthy for most adults, while sleeping just four to five hours per night typically leads to deprivation. Not only will lack of sleep make you more likely to gain weight, but it can also have serious health consequences, such as increased risk of auto accidents, diabetes, heart disease and mental illness, as well as reduced ability to concentrate.