Leptin and Ghrelin: The Master Keys of Appetite Control
Posted Feb 08 2011 1:31pm
You ever just sit there after devouring a whole pizza pie and chasing it down with a triple-size ice cream sundae and wonder why you are still hungry? Your belly has morphed into the size of Kayne West’s ego and the struggle not to eat another morsel out of guilt or lack of “will-power” is dominating your self-control. It might not be a lack of will power but something stronger than that; two hormones called leptin and ghrelin are the culprits. In this article I will explain how these two appetite hormones possibly control if we take another bite of fast-food meal or an organic snack.
Leptin, a protein hormone is produced by our body’s adipose tissue (fat cells). Our adipose tissue is actually an endocrine system that manufactures many protein hormones as well as insulating the body and storing energy. It sends a signal to the brain to let us know we are full. Ghrelin is a growth hormone that is produced in the stomach and pancreas that stimulates hunger. When our body’s energy reserves are low or even depleted, ghrelin make the body store fat to conserve energy. It slows down the breakdown of fat stores so that energy is not further depleted.
The hypothalamus is sensitive to these hormones. Leptin and ghrelin are part of a balancing act. They act in opposing ways when the level of one is low and the other is elevated. It’s a delicate scale dictated by balancing our blood sugar levels.
These hormones are also very sensitive to sleep patterns that impact our eating habits. When we are hungry, leptin tells the hypothalamus that blood sugar levels are very low and the body needs glucose, so we must eat. The liver, which converts food into glucose, signals the lateral hypothalamus to prompt us to either enjoy an organic apple and some raw cheese, or go visit a fast food drive-thru. Leptin will send a signal to your brain to let you know you have eaten enough food; satiety sets in to tell you to stop eating. In some studies leptin is more sensitive to starvation than to actually overfeeding, their levels will fall significantly during starvation but do not rise significantly due to overeating.
Ghrelin appears to behave independently of leptin due to sleep deprivation, which increases our appetite, especially for high-carbohydrate foods. This is why we see people snacking on chips, cookies or go to the diner for their cheese-fries fix after staying up late. Sleep deprivation is responsible to about forty percent decrease in blood glucose tolerance, which is associated with decreased insulin sensitivity. Despite the considerable research on ghrelin, scientists are still not sure the exact nature of the relationship between levels of this hormone and obesity.
The problem I see with overweight individuals is that they have other systems out of sync. Their inability to burn excess fat is due to factors like insulin-leptin resistance, a toxic liver and the constant consumption to sweetened beverages and processed foods. Studies have show people who are insulin resistant are also leptin resistant. The hypothalamus fails to recognize the satiety response created by high leptin levels. This is why overweight individuals continue to eat because their bodies cannot tell when they have eaten enough. This malfunction in the hypothalamus-leptin-ghrelin pathway is a condition called “hypothalamic-obesity”.
One of the best to take control of these hormones is to eat small meals through the day that contain healthy sources of proteins (organic meats, gelatins, broths), carbohydrates (root and non-starchy vegetables, ripened tropical fruit), and saturated fats (coconut oil, butter, ghee) in combination with each other. These foods will assure you balanced blood sugar levels throughout the day that will help control hormonal balance and weight control.