Grapefruit extract

Grapefruit is often used in weight loss programs to reduce appetite, due to its stimulation of the hormone cholecystokinin, which plays a role in the body’s digestive process. Grapefruit also contains a high amount of vitamin C, making it a common defender from the common cold.
The chemical that gives the grapefruit its aroma, nootkatone, http://ajpendo.physiology.org/content/299/2/E266.short, stimulates energy metabolism and helps prevent diet-induced obesity.