Yesterday I wrote about working conditions that may contribute to the obesity rate seen in people engaged in the nursing profession.
It created a flurry of replies that discounted the notion that shift work has any effect on body weight. Some readers said that shift work was not a valid reason for being overweight.
They’re right. I never meant to imply that shift work causes obesity. If shift work interferes with sleep or the shift worker has more things to do before or after completing a shift that prevent getting quality sleep, that could make a difference in weight management.
I’m sure there is somebody reading this right now who is thinking, “I don’t get much sleep and there’s not an ounce of fat on me.”
Before we go down that road, let me say right now, “Every sleep deprived individual will not become fat or if already fat, be unable to lose weight.”
Having said that, science is showing a direct link between sleep and weight in some individuals.
If you are gaining weight or are overweight and want to lose weight you would be wise to pay attention to your sleep habits.
What are scientists learning about hunger and satiety hormones?
Before the mid 90s we didn’t know much about what made us hungry or how we recognized we had enough to eat. It was assumed a stomach that had been empty for some time triggered hunger. Likewise when the stomach was filled with food, hunger was replaced with satiety or the feeling of having eaten enough for the time being.
There is a hormone that is also associated with hunger.
It’s called ghrelin. It’s produced by specialized cells that line the stomach and the pancreas and was discovered in 1996.
Ghrelin is one of the main hormones to stimulate hunger. Ghrelin levels increase before meals and decrease after meals. This is a mechanism that has its roots in the brain, the hypothalamus to be specific.
“If the lateral hypothalamus is removed (as seen in animal studies), feeding becomes less frequent leading to severe weight loss and death. If the ventromedial hypothalamus is removed, feeding increases, leading to weight gain and severe obesity.” - Ghrelin – What is Ghrelin?
The effect of ghrelin, the “hunger hormone” is counteracted by another hormone that is produced by the fat or adipose tissue in the body. This hormone tells us we have had enough to eat. In other words it makes us feel full after a meal.
In 1995, one year before ghrelin was discovered, leptin was discovered.
It’s a hormone that regulates metabolism and body weight. Leptin interacts with an important brain receptor. The discovery of leptin is responsible for giving researchers from the University of Michigan insight into possible ways of combating obesity, metabolic disorders, and some inflammatory diseases, according to a report published in Molecular Cell.
“Leptin, like insulin, is a hormone and it’s part of a network of regulatory hormones which control how energy is consumed and used up in the body. Resistance to leptin, or a lack of it have been associated with obesity.
“Leptin and ghrelin are two hormones that have been recognized to have a major influence on energy balance. Leptin is a mediator of long-term regulation of energy balance, suppressing food intake and thereby inducing weight loss. Ghrelin on the other hand is a fast-acting hormone, seemingly playing a role in meal initiation. As a growing number of people suffer from obesity, understanding the mechanisms by which various hormones and neurotransmitters have influence on energy balance has been a subject of intensive research. In obese subjects the circulating level of the anorexigenic hormone leptin is increased, whereas surprisingly, the level of the orexigenic hormone ghrelin is decreased. It is now established that obese patients are leptin-resistant. However, the manner in which both the leptin and ghrelin systems contribute to the development or maintenance of obesity is as yet not clear.” – The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review
In addition to the discovery of these hormones, scientists discovered that people who get less than six hours of sleep were 27% more likely to be overweight than those who got seven to nine hours of sleep.
You don’t have to take my word for it. An article published in the Huffington Post Sleep Deprivation Could Spur Hormonal Changes Linked With Obesity, Review Finds should convince you that there is a connection between sleeping and eating behaviors.
While there are plenty of people who show open contempt for obesity and more who hide their contempt but who think obesity is a sign of poor character and a lack of self-discipline, perhaps this will open your eyes to how a lack of shut eye may be a real cause of obesity and not simply an “excuse.”