Hunger & HORMONES

Two hormones stand out as having major influence on appetite: ghrelin and leptin. Ghrelin, known as the hunger hormone, stimulates appetite and promotes fat storage. When you’re hungry, your ghrelin levels are high, and eating brings them back down. There is some evidence that eating protein at a meal may suppress your ghrelin for longer, according to Dr. Kevin Murphy, professor of endocrinology and metabolism at the Imperial College London.

Leptin is sometimes called the satiety hormone because it can inhibit hunger. “High levels may try to push food intake down, but it is easy to overcome,” Murphy says. All it takes is the presence of something really tasty. “But low levels of leptin are a powerful signal for you to eat,” Murphy says. “Leptin is more of an antistarvation hormone.”

Many other hormones can also influence appetite through less direct means. For example, cholecystokinin (CCK) is released when we eat, and it helps slow and improve digestion and increase your feeling of fullness. “At high levels, it can seemingly reduce appetite,” Murphy says. Glucagon-like peptide 1 (GLP-1) is produced in the small intestine and helps you feel fuller, in part by slowing the emptying of the stomach.