Leptin and ghrelin are hormones in the human body responsible for making us hungry, or feeling full, therefore playing a huge part in controlling body weight. Everybody produces these hormones at different times. In order for our body to survive, it needs to recognise when it’s hungry and needs food, and also when it has enough reserves of energy in the form of body-fat stores.
Leptin is an appetite suppressor. It makes you feel full, as it signals to the brain that the body is in a well-fed state and is in no danger of starvation. The higher your body fat percentage, the higher your levels of leptin will be. However, people can become resistant to leptin, which can lead to obesity. Leptin is produced in the body’s fat cells, so the more fat you have, the more of the hormone you will produce.
Ghrelin is the hormone responsible for making you feel hungry. It is released in the stomach when the stomach is empty, therefore signalling to the brain that the stomach needs filling. Ghrelin levels will gradually rise until you eat, and, once fed, they will then remain reduced for about three hours after a meal, before steadily rising again.
Therefore, in order to help combat ghrelin, you should aim to eat smaller meals more often, to keep the stomach busy and satisfy ghrelin. A diet high in protein will also help to control ghrelin, as proteins take longer to break down and digest in the gut. By missing meals or starving yourself, you will be susceptible to bingeing due to feeling so hungry – with elevated ghrelin levels being the main culprit.
When bodybuilders get to very low levels of body fat, they will have very low levels of leptin, so eating small, regular meals won’t satisfy the hunger, even if it dampens down the effects of ghrelin. This is why the last few weeks of dieting are so difficult for bodybuilders. Most people will never need to get to such low levels of body fat, and so ghrelin will be the main hormone to control in order to diet successfully.