In order to know how much food to eat, the human body needs a way of assessing how much energy it currently has in storage. Leptin – more commonly known as the ‘fat hormone’ – essentially acts as our internal fuel gauge. It is made by fat cells and tells the brain how much fat the body contains, and whether the supplies are increasing or being used up. Food intake is regulated by a small region of the brain called the hypothalamus, which manages many of our hormones. When fat stores run low and leptin levels drop, the hypothalamus stimulates appetite in an attempt to increase food intake and regain lost energy. When leptin levels are high, appetite is suppressed, reducing food intake and encouraging the body to burn up fuel. It was originally thought that leptin could be used as a treatment for obesity. However, although it is an important regulator of food intake, our appetite is aff ected by many other factors, from how full the stomach is to an individual’s emotional state or food preferences. For this reason, it’s possible to override the leptin message and gain weight even when fat stores are suffi cient.
