Body Science
Sleep is the foundation on which the two pillars of good health, fitness and nutrition stand.
Ineffective, inadequate sleep is a detriment to any and all nutrition and fitness efforts. In fact, sleep deprivation can kill you. Every major system, organ, tissue cell, and even DNA molecule in your body suffers for lack of sleep. The effects of sleep deprivation are so severe that the Guinness Book of World Records stopped recognizing attempts to break the sleep deprivation record. The evidence of detriment is so compelling they then went on to delete past records out of fear that people would still make unrecognized attempts. Remember that the Guinness Book of World Records found it acceptable that Felix Baumgartner should ascend 128,000 feet into the outer reaches of our atmosphere in a hot-air balloon and free fall back to earth wearing only a spacesuit, passing through the sound barrier and creating a sonic boom with only his body along the way. They appropriately deem the risks associated with sleep deprivation to be much, much higher than this… because they are.
While the ways in which sleep deprivation can harm you are vast and wide and I encourage you to learn more about this topic, in this article I’m going to focus specifically on how sleep deprivation leads to both weight gain and obesity.
The hormones Leptin (from the Greek word leptos, meaning slender), and Ghrelin (ghre from the Proto-Indo-European term for growth) control your appetite. Leptin triggers a sense of satiation, while ghrelin triggers hunger. When circulating levels of leptin are high, you don’t feel like eating, while in contrast as ghrelin levels increase, you get the strong desire to eat. In a research study by Dr. Eve Van Cauter at the University of Chicago, a series of healthy young adults of perfectly normal weight showed that under controlled conditions these individuals were far hungrier when sleeping only 4-5 hours a night, than when the same individuals were given 8 or more hours of sleep. Hunger increased rapidly, by just the second day of sleep deprivation. Medical testing proved that inadequate sleep decreased the circulating levels of leptin, and increased the levels of ghrelin. This shows that sleep deprivation leads to loss of hunger control on a metabolic level. As Cauter described, “a sleep deprived body will cry famine in the midst of plenty.”
The same researcher conducted a number of other studies restricting participants sleep under controlled conditions while allowing them free access to a variety of foods. Researchers meticulously counted the calories that each participant consumed. On average, when getting insufficient sleep, participants consumed 300 -330 calories more per day over what they were routinely eating with adequate amounts of sleep prior. Furthermore, under-slept the participants opted to select higher calorie, less nutrient dense snacks foods like chips and cookies, over whole real foods. To put this in perspective, 300 calories a day, every day for just 11 months (let’s assume you slept well and ate well for the other month in the year), equates to 70,000 extra calories per year. That is the equivalent of 10lbs-15lbs of weight gain every year as there are approximately 3500 calories in 1 pound. It turns out that sleep deprivation increases the circulating levels of endocannabinoids, which are chemicals produced by the body that are very similar to cannabis. Like marijuana use, endocannabinoids stimulate appetite and increase the desire to snack. Midnight snack munchies anyone?
In another study, the last that I will discuss in this brief article, researchers took a group of overweight men and women and placed them on a low calorie diet for two weeks, while they stayed in a medical facility for controlled observation. One group was restricted to just 5.5 hours of bedtime, while the other was given 8.5 hours in bed. While both groups lost weight, testing was conducted to determine what sources the weight loss came from for each. In the group who was given just 5.5 hours to sleep more than 70% of the pounds lost were from muscle tissue (leaving just 30% to come from actual fat), while in the group that was offered the adequate 8.5 hours to sleep showed a more favorable 50% of the weight loss came from fat tissue. If you’re looking to lose weight, you must consider what kind of weight is it you want to lose. I ask my nutrition clients this time and time again, as the type of food they eat will affect these results. So too will the amount and quality of sleep you get, it turns out.
So how much sleep should you be aiming for? Adequate sleep for adults (all adults – you do not need less as you age, you just think you do) is 7-9 hours, with 8 hours minimum being optimal.
Most of the information I’ve shared here, was extrapolated from the book “Why We Sleep” by Dr. Matthey Walker PhD. While I intend to write more on sleep in the future, if sleep is an interesting topic for you, and you’d like to know more, I highly recommend this read. There is much, much more to learn from this book.
