This was followed by the first human clinical trial conducted by Phytopharm in which a group of morbidly obese men and women was chosen from Leicester, England, and placed in a "phase 1 unit", a place as close to prison as it gets. All the volunteers could do was read, watch television -- and eat. Half the group were given Hoodia and half were given a placebo. At the end of 15 days, the group on Hoodia had reduced their food intake by 1000 calories a day. Given the average daily diet is around 2200 calories, this was a stunning success.

More recently, in two double-blind studies (the only proof accepted by the established scientific community) lean and obese laboratory rats were given Hoodia which strongly suppressed their appetites and caused major weight loss in the obese rats and moderate appetite suppression and weight loss in the lean rats. Hoodia also induced a modest drop in the rats’ blood sugar levels, and no adverse side effects were reported.

References

Van Heerden FR, Vleggaar R, Horak RM, Learmonth RA, Maharaj V, Whittal RD. Pharmaceutical compositions having appetite suppression activity. United States Patent 6,376,657, issued April 23, 2002.
Tulp OL, Harbi NA, Mihalov J, DerMarderosian A. Effect of Hoodia plant on food intake and body weight in lean and obese LA/Ntul//-cp rats. FASEB J 2001 Mar 7;15(4):A404.
Tulp OL, Harbi NA, DerMarderosian A. Effect of Hoodia plant on weight loss in congenic obese LA/Ntul//-cp rats. FASEB J 2002 Mar 20;16(4):
Habeck M. A succulent cure to end obesity. Drug Discovery Today, March 2002, pp 280-281.