Is lack of sleep making you fat?

By Jade Teta ND CSCS and Keoni Teta ND, LAc, CSCS

Sleep is one of the most basic physiological responses in the animal world. Everyone knows that you can’t function for long when you are sleep deprived. Sleep can be regarded as the physiological equivalent to the reset button on your computer. When a computer crashes, the surest way to solve the problem is to reboot. It seems we modern day humans have forgotten our intimate connection to sleep. We do everything we can to circumvent it. We stay up nightly watching late night TV, surfing the Internet, and feeding ourselves under artificial light. In the morning we rip ourselves away from the bed using all manner of stimulants to jumpstart our bodies and allow us to function once again. Like most things in the modern world, sleep is treated as more of an annoyance than a critically essential process for whole body function. It is not uncommon for people to brag they only require four hours of sleep. However, in order to keep them functional, it requires large cups of coffee, along with plenty of bagels, cookies, chocolate, pasta; you name it. Most of these people are self-diagnosed carbohydrate junkies and regard their weight issue as a hereditary defect rather than a symptom of chronic sleep deprivation. The loss of fat from the human body is a complex process that goes far beyond simple one-dimensional models of calorie counting. Sleep holds the key to restoring your fat burning software and it is all related to ancient human metabolism.

Sleep and Hormones

You may be thinking, what can sleep possibly have to do with fat metabolism. Well, you have heard of hormones right? Hormones in the body are powerful chemical messengers that tell the body how to respond to the outside world. When most people think of hormones, they think of the sex steroids like estrogen, progesterone, and testosterone. These are definitely examples of hormones, but there are many different types of signaling molecules in the body and they extend beyond concerns of reproduction. Maybe you have heard of some of the key hormones involved in fuel metabolism? Insulin, leptin, cortisol, adrenaline, growth hormone and others act like computer software to the body. They give the body instructions about how, when, and why to respond to the outside world. Survival is the major concern of any species, and hormonal regulation of fat metabolism has been essential to human existence for millennia.

If hormones are the body’s computer software, than the sense organs are its input devices. Your eyes, ears, nose, mouth, and sense of touch, temperature and perception are analogous to the mouse, keyboard, CD drive, Internet connection, and input devices on your computer. Just like typing a command into a computer keyboard or loading a new program on your computer hard-drive, signals coming in from your body’s sense organs are the prime movers of hormonal metabolism. Easily the most important signal received by the body is light. Light influences metabolism so acutely that studies have shown a single photon of light shining into the back of the knee in an otherwise blacked out environment, can elicit a hormonal response in the body. Here is how light works: as the sun rises, those first beams of light hitting your closed eyelids send signals to the body’s nervous system. These signals produce a hormonal response characterized by a slow, steady climb of stress hormones; adrenaline, nor-adrenaline, and cortisol. These hormones then began to raise blood sugar, increase respiration, stimulate fuel metabolism and elevate energy to wake you from sleep. From there, you are off. The body receives environmental inputs and issues hormonal commands all day long. Food, sounds, light, exercise, stress, and beliefs provide the stimulus for hormonal reactions that determine whether you burn fat or store it, age fast or slow, or maintain a state of health or disease. The power of your choices to affect hormonal balance is profound. Sleep more than any other choice has the power to balance your hormonal software for the coming day.

Sleep, the ancient fat regulator

Before getting to the specifics of how sleep elevates fat burning, it is important to clarify what we mean by weight loss. We have all heard of calories and most in the fitness world feel calorie burning is the end all be all of weight loss. The first thing to understand is weight loss is an inaccurate descriptor of what most desire. Fat loss is what people really want, and weight loss does not necessarily equal fat loss. That is why a focus on calories is so misleading, because the type of calorie burned, whether fat or sugar is what is most important. Hormones determine how much and what type of calories will be burned. Most people’s bodies are programmed to burn sugar and conserve fat. This is an ancient survival mechanism that evolved to help our ancestors survive periods of famine. For almost all of human existence food was not guaranteed and those who were able to conserve fat easily fared better. However, there are and always have been environmental signals that told the body to burn fat. Light and sleep are the major determinants.

Why does sleep have this effect? Consider the role light and sleep have played in our evolution as humans. For millions of years we evolved with the seasons. Summer days are longer, brighter, and accompanied by abundant food. Winter days have longer nights, colder days, and less food. This may seem obvious, but before the amenities of artificial light, heat, and readily available and processed foods, the only option at night was to sleep. Summer and winter in the natural world send distinct and clear signals to a mammal’s physiology. In the case of summer, the lengthened days meant elevated stress hormones like adrenaline and cortisol. The excess food meant higher amounts of insulin to signal fat storage and leptin to increase hunger. The whole goal of summer is to mate and then eat as much as you can to get fat for the coming winter. As fall approaches, the body has been exposed to high amounts of the stress hormones, insulin, and leptin for so long it becomes resistant to their action creating a unique state where the ability to use fat or sugar for fuel is compromised. Sound familiar? This is the modern day equivalent of what doctors call metabolic syndrome. To ancient man reaching this state of hormone resistance was essential to surviving winter. Without high sugar, blood fat, and ample fat depots, the chances of surviving a long cold winter were diminished.

For a mammal wanting to get through the long winter, hormone resistance is good news because it means the body is now nothing but a fat storing machine. By the time winter dawned historic humans would have shown a decreased ability to use fuel, lack of motivation, depression of all body functions, and fatigue.  This is exactly the response needed to induce hibernation in a harsh prehistoric winter. Jovial energetic cavemen with low body fat would not have lasted long. This is identical to any mammal’s preparation for hibernation and can describe many modern day humans. Winter was our prehistoric savior. The shorter days and longer nights of winter forced prolonged periods of sleep.  Sleeping throughout the winter reversed the hormone resistance that was so prevalent in the late summer months.  Less light exposure, a complete reliance on animals for food, and prolonged sleep induced a new hormonal program that turned on all the fat burning genes. By the time spring returned, the body was primed for action and burning through its fat stores at an accelerated rate. The problem for modern man is we have induced an artificial summer that never ends. We have a constant and steady supply of sugar-rich foods. We keep the temperatures stable through heating and air conditioning. And most importantly, we extend our days and decrease our sleep through exposure to artificial light in the form of TV, computer and the light bulb. In this artificial summer, winter never comes, yet we continue to respond as if we were in the natural world. Leptin, insulin, and cortisol run a hormonal program instructing us to eat as much as we can to get fat for the coming winter. The result? We get fatter, more tired, and more depressed. Sleep is the way out.

Does science support sleep as a fat burner?

Maybe you are wondering if our theory holds up in the scientific world. Is there any objective data to support what we are saying? One study published online at the Public Library of science illustrates how sleep is connected to hormones that control appetite. This study published December 7^th 2004 looked at 1,024 subjects and their sleep and eating habits. In subjects who slept less than 7 to 8 hours a significant increase was noted in BMI and appetite. These short sleepers ate significantly more and weighed more than those people who slept longer. The study also showed that leptin and ghrelin, two key hormones regulating appetite, were the major reason for this finding.

Another more recent study bolsters the fact that light and lack of sleep are related to obesity. This study published in the June 2006 International Journal of Obesity, was a very comprehensive study wanting to discover all the factors related t the increasing prevalence of obesity. In addition to the well-recognized connection between diet and exercise, this study found something interesting and unexpected. It found that deficits in sleep were a major predictor of weight gain and obesity. This study also showed that heating and air conditioning were playing a role. This lends strong support to the fact that human avoidance of natural factors such as light and temperature has caused hormonal confusion as to how to manage our fat stores. The two studies above, and others like them, lend serious credibility to the artificial summer hypothesis and show that key hormones related to fat burning are altered negatively with reduced sleep.

There are many other studies on circadian rhythm, sleep and hormone balance, and increased appetite in the sleep deprived. The important thing to remember is that you don’t need science to tell you what makes sense intuitively. Most people know that if they get a good nights rest, they are more likely to feel energetic, motivated, and make better choices. However, it is not always easy to know exactly what you can do to insure you get the most fat burning potential from your sleep.

Choosing sleep

It all starts with your choices. Don’t get the wrong idea, we are not telling you to go hang out in a cave for three months and hibernate. We realize the demands of life. We know you are busy, work hard, exercise, and try to find time to do the things you enjoy. However, we also know that if you are serious about fat loss, you will need to consider some changes. You have to ask yourself what is more important; do you want to burn fat, or watch your favorite late night TV show.

Frequently people do not feel tired and take that as a sign they should stay up until they can go to sleep. This is the wrong choice. How to you think your body is going to feel when you feed it high sugar foods all day and bathe it in artificial light. It is going to feel like it is summer. What do animals feel compelled to do in summer? They want to find food and be active. Have you ever wondered why people who sit down in from of the TV at night always feel compelled to make their way to the refrigerator? Feeling tired is no longer a reliable indicator of the need for sleep because everything in the environment is sending the hormonal signal to stay awake. The only way to change this is make different choices.

Technology can help. Using dimmers on your lights and computer screens can decrease stress hormones at night. Using candles is another option. Tivo and other recording devices are available to record your favorite late night TV shows, so you can go to be closer to sundown. There are all kinds of ways to send your body proper signals and rewrite your hormonal software programs. Here are some pointers to help.

8 hours is minimum; 9 is optimal

The body needs long hours of uninterrupted sleep for hormonal balance. Every night your body goes through its rhythm of hormonal computing to repair, regenerate, and revitalize the tissues of the body. This process is complicated and takes time. At least eight hours is necessary, but nine is best.

When downloading a new piece of software on your computer, things happen in sequence and are done meticulously so the software will function correctly. It is no accident that whenever you download new software on a computer you have to restart. If the process is interrupted, you have to reboot and start again. It is similar in the body.

Time is essential for your body’s hormonal software to download and complete its functions. As the hours pass during sleep, your fat storing hormonal machinery is turned down. Leptin, cortisol, insulin, and adrenaline are lowered. This allows the body to respond to the signals of these hormones once again. At the same time, glucagon, HGH, testosterone, and other growth promoting and antioxidant hormones like melatonin increase their activity.

The combination of this hormonal environment signals the body to burn fat. It is important to remember this process takes time. The longer you sleep the better chance you have of enjoying several hours of fat burning. If you sleep less than 8 hours a night you may never reach fat burning at all.  Nine hours of sleep assures maximum fat burning potential

By 10pm is best

           

Your natural sleep cycle is also related to time. Remember, light is what turns on your hormonal wake-up software. If you are exposed to light at night you will not be able to easily switch into relaxing sleep. Some people are more susceptible to this than others. Your physiology is programmed to go to sleep shortly after sundown. Artificial lighting, TV, and computer screens circumvent this response by lengthening the time your hormonal wake software is active. The longer you are exposed to light after sundown the more you push back your hormonal sleeping signals.

Parts of these signals include fat burning and anti-aging hormones like HGH, glucagon, and testosterone. When light comes up again the next morning, these hormones are shut off. This means sleeping eight hours, but going to bed at midnight only gives you five or so hours of sleep in the dark. This is not long enough to reset your hormones and commence fat burning. People going to sleep closer to midnight have higher cortisol levels in the morning than those going to bed around ten o’clock. This is true even if both groups of people get equal amount of time sleeping. To insure your fat burning hormones are working, the time you go to bed is just as important as how long you sleep.

Turn the lights out

                       

There are things you can do to minimize the effect of light after sundown. Dimmers allow enough light so that you can see, and more closely resemble moonlight than sunlight. Candles create a similar effect. By using dimmers and candles you can help sleep quality and quantity. TVs and computers are equipped with dimmers too. 

Don’t eat before bed

If it is difficult for you to sleep properly, than you can simulate sleep’s affects by avoiding food at night. Sleep is incompatible with eating which is one important benefit. Good sleep quality and quantity creates the optimal situation for lasting weight loss: lower calories and hormonal balance. One of the most effective tools for fat loss is the avoidance of food for at least 10-12 hours every night. That means the last meal of the day will need to be around 7 or 8pm for most. Staying away from food after the sun goes down helps reverse the hormone resistance of cortisol, insulin, and leptin and makes you a far more efficient fat burner.

Sweet Dreams

By now, we hope you have gotten the point. Calories, drugs, surgeries, supplements and the latest magic rainforest juice may provide some benefits, but can never rewrite your ancient hormonal program to which your genes and metabolism are tuned. Sleep can. Getting back to sleep is like loading a brand new software program into your body. It tells the body to decrease insulin and leptin. It lowers cortisol and other stress hormones, and it has direct power over fat burning hormones like human growth hormone. Now that you understand how your ability to burn fat is directly impacted by sleep, you can construct an environment that is more in line with your ancient metabolic processes. Sweet dreams.