If you ask the average American what’s on their wish list for improving the quality of their lives and the way that they feel, most people will have either losing weight or getting more sleep at the top of their list. The funny thing is that there’s a good chance that if they accomplish one, the other will follow. There’s a growing body of evidence indicating that sleep and obesity are closely tied to one another. Not only do sleep-deprived people have a higher risk for obesity, but people who are obese have a higher risk of experiencing trouble falling asleep, and also have a high potential for being diagnosed with obstructive sleep apnea, a serious health condition.
So does that mean that if you want to lose weight you can do so by going to sleep earlier? As hard it may seem to believe, the answer is actually yes. Of course you are still responsible for cutting calories and getting more exercise, but research has shown that sleep deprivation makes a couple of your appetite-controlling hormone levels go haywire. Being sleepy can make you crave unhealthy foods and make misguided selections even when you’re not actually hungry and even impacts the way that your body processes the food that it eats and predisposes you towards diabetes.
According to Kristen Knutson, assistant professor of medicine a the University of Chicago, a number of studies have shown that those who sleep less than six hours per night have a much higher risk for being obese. One study showed that when healthy people between the ages of twenty and thirty were sleep deprived and kept to just fours hours of sleep per night, their appetite hormone levels shifted dramatically, with leptin, the hormone that makes us feel full, declining, and ghrelin, the hormone that makes us feel hungry, increasing. Once given the chance to eat, the sleep deprived study participants were making noticeably bad choices, reporting cravings for sweets, cookies and high carbohydrate, starchy foods rather than healthy options such as lean proteins or fresh produce.
In addition to shifts in hormone levels, sleep deprivation also makes people’s metabolism levels drop. When Orfeu Buxton, an assistant professor at Harvard Medical School and an associate neuroscientist at Brigham & Women’s Hospital lead a study in which 21 participants sleep, diet and activities were restricted to approximate the same impact as jet lag or shift work, they experienced an eight percent drop in their resting metabolic rate. According to Buxton, “This equates to a potential of ten pounds of weight gain in a year, with diet and exercise remaining the same.”
Of even more concern is the fact that the weight that is likely to be gained as a result of a lowered metabolism is likely to be abdominal fat. According to Lori Roust, an endocrinologist at the Mayo Clinic in Scottsdale, Arizona, the way that we put on weight is directly related to our levels of cortisol. Though cortisol is known as the “hormone of well being”, that is true for when it is elevated when it is supposed to be, between 7:00 in the morning and 8:00 in the morning. Cortisol levels are then supposed to diminish over the course of the day until they reach their lowest levels at night. Roust says, “When people don’t sleep at night or have a medical problem that doesn’t allow them to sleep well (such as sleep apnea,) you get higher levels of cortisol at night, which promotes weight and fat gain, mostly in the interabdominal region, which is a link to a predisposition of diabetes and heart disease.”
Finally, the studies that have been conducted to determine the relationship between sleep and weight have also found an alarming link between interrupted sleep or lack of sleep and a propensity towards developing diabetes. One of the most important tasks that our bodies accomplish is the appropriate processing of the food that we eat, breaking it down into various sources of energy, muscle, bone and waste. Excess food can be stored as fat or converted to sugar. Buxton’s study showed that when subjects were deprived of sleep it had a direct impact on the way that the pancreas functioned. One third less insulin was produced, which is a serious impact because insulin is what turns sugar in our blood streams into energy. When there is too much sugar in our system it can easily lead to diabetes. Of even greater concern is that this effect is not something that only happens to older people or people who are unhealthy – it is not determined by age or gender.
With so much evidence pointing to the fact that lack of sleep is definitively linked to making us gain more weight, the obvious question that follows is whether or not getting more sleep can help us to lose weight. There is no question that people who get a full seven to eight hours of sleep per night on a regular basis are likely to have much more energy, to be more clear-headed and focused, and to feel better in general. Between the fact that they are no longer experiencing the negative impacts of sleep deprivation, slowing down their metabolism and increasing their cravings for unhealthy food, and the fact that they are feeling more energized, there is a good chance that sleeping well can be one of the best ways to jump start a diet. One of the best ways to combine the best of all worlds is to get a full eight hours of sleep by going to bed early and getting outside into the morning sunshine for a fifteen minute walk. Not only will the morning light help you to set your circadian clock so that you will more easily wake up in the morning and get drowsy at night, the walk will burn calories. Plus there is evidence that morning exercise also helps you get the restorative sleep that you need!