Like many things in the human body, cravings and appetite control are regulated by hormones. Leptin and ghrelin are both naturally occurring hormones within the body that affect appetite. Leptin is created by fat cells and decreases appetite, while ghrelin increases appetite. The body’s sensitivity to these hormones is what creates our feelings of hunger. An increased resistance to leptin would make the subject’s appetite increase and vice versa for an increased resistance to ghrelin. Understanding these hormones is the key to controlling appetite and creating a diet that is healthy for the individual’s body.
Ghrelin is a hormone that is most released within the stomach. Its primary role is to induce hunger and signal it to the brain. Studies have shown that ghrelin levels increase in those diagnosed with anorexia nervosa and decrease in those that are obese. It also determines how fast hunger returns after a meal. Ghrelin levels usually increase greatly before one eats and decrease for a few hours after a meal. Afterwards, the cycle repeats as hormones usually do. Within this cycle, another hormone is used by the body to control appetite, leptin.
Leptin is a hormone that tells the brain that the body has enough food for energy. It increases and decreases with ghrelin to create a healthy appetite for the individual’s body. Despite this, the body is able to develop a resistance to the hormone. This is shown in obese subjects who have higher leptin levels, but do not respond to the signals. A study on rats whom were given doses of leptin showed that the appetite suppressing effects lasted only about two weeks before a resistance was developed. This may also be the case with increased ghrelin levels in individuals with anorexia nervosa. There are other factors that are shown to affect ghrelin and leptin levels in the body.
Studies have shown that factors like sleep, diet and time since last meal also affect ghrelin and leptin levels. A study conducted on twelve men showed that sleep deprivation increase ghrelin levels, inducing cravings and hunger. It also showed that sleeping less than 8 -10 hours can cause the same effects. Diet is also very important in regulating these hormones. Eating high-fat foods has been shown to disrupt the signals the hormones send to the brain. This leads to eating more calories, gaining weight and storing fat. While this is true, research has also shown that high-carb diets and high-protein diets suppress ghrelin even more than a high-fat diet. This means that a mixed diet is the best to keep ghrelin levels maintained.
In conclusion, healthy habits including sleep and diet are very helpful in controlling these hunger hormones. Ten hours of sleep is enough to keep your ghrelin levels normal and a mixed diet of carbs, fats and proteins will keep these hormones in check better than a diet rich in only one. These recommendations will help control appetite and maintain a healthy weight.