To keep extra pounds off, don’t just go to the gym. Go to bed. If you have been having difficult time losing weight despite exercising religiously and eating piously, the answer lie in your bed. Lack of sleep, even just an hour a day, could be part of the reason you can’t lose those extra pounds.

Scientist don’t know exactly why not enough sleep can cause weight gain but they believe that three hormones are involved. Leptin has been called the “satiety hormone” because it tells you to stop eating when you are full. Low levels can make you eat more food than you need since you don’t feel satisfied and it can also make you crave carbohydrates regardless of the amount of calories consumed. Cortisol is a stress hormone that increases your appetiate and directs fat to be stored in the abdomen. Growth hormone isn’t just to make children grow. In adults, it repairs muscles and regulates muscle to fat ratio.

Less sleep, more calories.

A 1999 University of Chicago study found that lean young men who slept four hours a day for 16 days had decreased levels of leptin and increased level of cortisol. These hormonal changes made them so hungry that they consumed 1,000 extra calories a day. Survey done in hospitals across the US found that 90 percent of nurses who worked the night shift of 11 pm to 7 am were more likely to gain weight. Other researchers found that people who lack sleep can eat as much as 10 to 15 percent more calories. The theory is that the body may subconsciously be trying to make up for lowered energy levels.

You might think nothing happens while you are asleep but actually your body and brain are busy doing repair and maintenance work. There are two types of sleep: REM or Rapid Eye Movement sleep when you do most of your dreaming, and non-REM sleep when you are physically restored. Non-REM sleep comes in four stages. Stage one is a state of drowsiness. Stage two is light sleep while stage three and four are deep sleep. During deep sleep, your body repairs tissues including the skin. Typically, men get less deep sleep as they get older. Women get greater amount of deep sleep than men until after menopause when their sleep patterns become similar. Growth hormone production reaches its peak during deep sleep (specifically between midnight and 2 am) so less time spent in this stage of sleep means less growth hormone. The result? A harder time losing weight, more fat in the abdominal area, and less muscle mass and strength. Although young and middle-age men sleep the same number of hours, researches have disvoreded they are not getting the same amount of deep sleep. Men who are 25 years old and below get 20 percent deep sleep while those between 25 to 35 years get 12 percent. After age 35, it’s 5 percent or less. This may explain why even very fit middle-aged men complain that they have stubborn love-handless they can’t get rid of.