As sleep goes down, weight goes up….

Now, blessings light on him that first invented sleep! It covers a man all over, thoughts and all, like a cloak; it is meat for the hungry, drink for the thirsty, heat for the cold, and cold for the hot. It is the current coin that purchases all the pleasures of the world cheap, and the balance that sets the king and the shepherd, the fool and the wise man, even. ~Miguel de Cervantes, Don Quixote, 1605

Lots of recent fuss over getting enough sleep concerns links between lack of sleep and weight gain.  As sleep goes down, weight goes up. If you’re not interested in weight or body composition, look away. Nothing to see here. I’m not interested in dieting but I am interested in changes we can make that have an effect on nutrition, metabolism, and ultimately weight and body composition.

First, the correlation: Is lack of sleep making me fat?

With an ever-increasing number of studies finding a direct connection between sleep deprivation and weight gain, it’s difficult to deny the cause-and-effect relationship. People who get at least seven hours of sleep per night tend to have less body fat than people who don’t. There are, of course, other factors involved in determining who becomes overweight and who doesn’t, like food intake, exercise and genes. But sleep is a more integral of the process than most people realize. In a study involving 9,000 people between 1982 and 1984 (NHANES I), researchers found that people who averaged six hours of sleep per night were 27 percent more likely to be overweight than their seven-to-nine hour counterparts; and those averaging five hours of sleep per night were 73 percent more likely to be overweight.

Second, it’s not just weight, also fat versus muscle:  Lack Of Sleep Can Make Dieters Lose Muscle Instead Of Fat

People who are on a low-calorie diet will lose the same amount of weight whether they sleep an average of 8.5 hours or 5.5 hours each night. However, those on 8.5 hours will lose much more fat, while those on 5.5 hours lose mainly muscle, instead of fat, according to an article published in the peer-reviewed journal Annals of Internal Medicine. The researchers, from the University of Chicago stress that adequate sleep is a key contributor to managing body weight.

 

Third, what’s the causal mechanism?:  Insufficient sleep affects appetite and satiety hormones as well as fat cells, according to the nation’s top sleep experts.

Most people know they should cut calories and exercise more to trim down, but there’s now significant scientific evidence that another critical component to weight control is avoiding sleep deprivation, sleep scientists say. “There is no doubt that insufficient sleep promotes hunger and appetite, which can cause excessive food intake resulting in weight gain,” says Eve Van Cauter, director of the Sleep, Metabolism and Health Center at the University of Chicago. She has spent 15 years studying the topic. Sleep deprivation probably affects every process in the body, she says. “Our body is not wired for sleep deprivation. The human is the only mammal that does this.” Her research and that of others may help explain why so many people who are chronically sleep-deprived also are overweight, and it could be part of the reason sleepy college students, new parents and shift workers pack on pounds.

Fourth, and this fascinated me, we’re the only animals who do this:

“The human is unique in sleep depriving itself.” According to Van Cauter, the only times that animals lose sleep is either when there is a shortage of food or a stressful situation.  Such behavior can also be seen in humans, though much more frequently.“Our biology is wired to interpret sleep deprivation as either corresponding to a lack of food or corresponding to major stress,” Van Cauter says. Such behavior explains why the late-night bowl of ice cream can seem so appealing.

Hormones play a significant role in regulating the body’s food intake, and Van Cauter says that regulation of the hormones that control hunger and appetite starts in the brain, specifically the hypothalamus.  In the hypothalamus are orexin neurons, which maintain wakefulness and become hyperactive when the body is sleep deprived.  When the orexin neurons are more active, they stimulate production of hormones that are associated with increased hunger and appetite. When more of these hormones are created, humans tend to crave sugary and fatty foods.  Van Cauter says the reason for such a dietary phenomenon is that the brain is fueled primarily by sugars and fats, and needs those to stay alert. Because of sleep’s profound impact on diet, Van Cauter says the success of any weight loss plan is dependent largely on the amount of sleep that the individual gets.

Many people may experience difficulty getting the proper amount of sleep and may be inclined to look for other ways to keep the weight off.  Studies have shown that the hormone lepton can reduce appetite, but its use in overweight subjects is limited because they have a resistance to the hormone.