Are you getting enough sleep? Probably not if you’re like most Americans. According to the American Sleep Institute, 60% of Americans say they don’t get enough sleep each night. This is not surprising. We live in a 24/7 world in which we are able to shop, be entertained, work and communicate every minute of every day. Most adults are familiar with the effects of sleep deprivation: falling asleep in the late afternoon, irritability, and loss of concentration, to name just a few. But there’s another consequence of sleep deprivation that is more insidious: it can make you fat.
The relationship between sleep deprivation and weight gain was first noticed more than a decade ago by researchers who charted sleeping habits of Americans over 50 years. In the 1960’s, the average American slept about 8.5 hours per night. Today we sleep less than seven hours per night. The increase in obesity has paralleled the sleep trend over the last 50 years. In fact, many researchers believe a primary cause of obesity is sleep deprivation. The less we sleep as a society, the more we weigh.
Scientists have identified just why sleep deprivation can put the pounds on. The answer is found in our circadian rhythm, or our normal 24-hour metabolic cycle. Our circadian rhythm is programmed into our genes. This programming, which evolved over thousands of years, ensures that our metabolism is as efficient as it can be. However, this mechanism only works if our lifestyle is in line with our genetic programming. Humans are hardwired to be primarily diurnal creatures. In other words, our bodies perform best in the daylight. This legacy can be seen in the fact that we never developed the sense of vision and smell that would enable us to hunt at night. In the daytime, the metabolic processes that control energy, stress and appetite work best. If we remain awake after nightfall, these metabolic processes become far less efficient. Our normal metabolism gets out of sync, our appetite is turned on so we eat more, we don’t convert food to energy, stress levels remain elevated-and we gain weight.
Public discussion of weight problems focuses on the amount of food we eat and the amount of energy we expend each day. We have all heard the slogan, “Eat less, move more.” The problem is that adhering to this simple advice causes enormous frustration for most people trying to lose weight. Eating less leaves us with less energy to move more-and less energy for everything else. It’s like reducing fuel consumption in your car by simply putting less gas in the tank, only to find that you can no longer get to work. An alternative is to increase the efficiency of the engine so it runs further with less gas. When we increase the efficiency of our metabolism we can eat less and still have more energy, and sleep is essential to maintaining the efficiency of our metabolism. Here are the four ways that sleep can help you lose weight:
Sleep Makes You Less Hungry
Our appetite is controlled by different types of proteins, some that turn hunger on, others that turn off appetite by making us feel full. When we don’t get enough sleep the proteins that turn off appetite are inhibited and those that tell us we are hungry are activated. Individuals who don’t get enough sleep not only feel hungrier during the day, but they are not satisfied as readily. The impact of sleep on appetite control is dramatic. One study showed that sleep-deprived individuals had a 28% increase in the proteins that turn on hunger and a simultaneous 18% decrease in the proteins that turn off appetite.
Sleep Decreases Daytime Stress Levels
The body’s primary stress hormone is cortisol, which has been identified as a key culprit in causing obesity. High levels of cortisol independently turn on appetite and at the same time cause a decrease in lean body mass. Our cortisol levels are controlled by our circadian rhythm. Normally, when we wake up from a full night’s sleep cortisol levels are high but they decline rapidly after breakfast. This is one of the reasons why you should never skip breakfast when you are trying to lose weight. However, when we fail to get enough sleep, cortisol levels remain elevated throughout the day, interfering with appetite regulation and increasing the conversion of food into body fat.
Sleep increases our body’s ability to burn calories
Researchers first made this observation in shift workers. They found that individuals who worked at night had a higher incidence of type II diabetes and obesity than the general population. Upon further investigation the researchers discovered that sleep deprivation interferes with normal insulin levels. Insulin plays a critical role in ensuring that the calories we eat are efficiently burned for energy. When we don’t get enough sleep our cells become less sensitive to insulin, and instead of being burned, food calories are converted to body fat.
Sleep Increases Lean Body Mass
Increasing lean body mass aids fat loss and maintenance of fat loss. The reason is quite simple: a muscle cell burns more calories than a fat cell. The more muscle we have the more calories we burn in a day. Sleep loss interferes with the body’s ability to manufacture lean muscle mass. With less lean muscle mass, extra food calories are converted into fat. The effect of sleep on lean body mass was shown by researchers at the University of Chicago who investigated the impact of sleep on two groups of subjects on a reduced-calorie diet. One group slept 5.5 hours per night and the other group slept 8.5 hours per night. Both groups lost similar amounts of weight, but the sleep-deprived group lost 50% less fat.
Sleep More – Get Slim
It would be magical if you could sleep your way to slimness. That would be even better than those weight-loss creams that supposedly make your body fat melt away while you are sleeping. Unfortunately, it’s not realistic. Getting more sleep will, however, make it easier for you to manage your weight by restoring your normal circadian rhythm. With adequate sleep you will get greater benefit from proper diet and activity habits as your body no longer fights your efforts to lose weight.
How much sleep is enough? Ideally, you want to get about 7.5 hours per night. That requires making some life choices. It is ironic that many individuals spend a great deal of time and money trying to lose weight without taking some simple measures to ensure their metabolism is operating at peak efficiency. It’s also important to understand that you can’t bank your sleep – you can’t get six hours of sleep per night during the week and catch up on the weekends. That’s because your circadian rhythm operates on a 24-hour cycle. Every 24 hours it resets itself. That means you can start to see the benefits of getting more sleep as soon as tomorrow!