Garcinia cambogia is any one of a genus of trees native to Australia, Asia and Polynesia. The trees bear tropical fruits which look similar to small pumpkins, and are commonly known as garcinias, brindleberries or mangosteens.
The mangosteen fruit is rich in nutrition, containing vitamins A, B6, B12 and C, and it's also a good source of dietary fibre. Mangosteens also contain calcium, iron, magnesium, manganese, potassium and zinc, so including them in the diet gives access to many essential vitamins and minerals.
The rind of garcinia is rich in hydroxycitric acid, also known as HCA. HCA inhibits citrate lyase, an enzyme which converts excess sugars into fatty acids, the leftovers of which are then stored by the body as fat. For this reason, foods rich in HCA are thought to help with weight control, as they effectively block the storage of fat.
Garcinia cambogia is therefore often sold as a weight loss supplement. Because HCA also increases the production of serotonin in the body, it can help to suppress appetite and cravings; garcinia as a weight loss aid is therefore thought to be particularly effective for emotional eaters.