Hoodia is making a name for itself after centuries of use by the Kalahari bushmen in South Africa. Apparently, Hoodia wards off hunger on bushmen's long treks; thus experts seem to think it can do the same for us urbanites.
Hoodia is a South African cactus, succulent. The theory goes like this: Hoodia influences the nerve cells in the brain area that controls hunger -- I like to know who figured that one out and tested the brain -- by reacting to blood glucose levels. Tricking the brain to thinking that the body is full.
The plus point about Hoodia is that it is not a simulant like most diet suppressant, weight-loss herbs.