There are many reasons why this link has been made. The first is that when sleeping, our bodies burn about as many calories as when we are laying on the couch watching television, but when we are asleep there is a much smaller chance that we will head for the kitchen during commercials for snacks and goodies to munch on throughout our favorite shows. Another simple explanation is that lack of sleep leaves us lethargic and unmotivated to do as much physical activity as we might if we received the proper amount of sleep

Studies have revealed more technical reasons behind the connection. First, lack of sleep causes a change to the body’s metabolism and could make losing weight harder for some people. Second, changes in hormone levels have been linked to sleep deprivation. One hormone, cortisol, regulates metabolism of sugar, protein, fat, minerals and water. Studies have shown that physical or emotional stress raises cortisol levels, which decreases regulation of metabolism. Lack of sleep may also raise levels at certain times of the day.

 In addition, higher levels of insulin, a condition known as insulin resistance, have also been linked to a shortage of sleep. Excess cortisol could be the link between them. Since insulin not only controls blood sugar, but also promotes fat storage, extra insulin makes weight loss more difficult.

 All together, more energy to exercise, better metabolism to lose weight, and less time to snack are all definitely propositions worth sleeping on.