As people were getting ready for the holiday season and its accompanying waist expansion late last year, Dr. Mehmet Oz let viewers of his TV show in on a timely little secret. "Everybody wants to know what's the newest, fastest fat buster," said the board-certified cardiothoracic surgeon and one of People magazine's sexiest men alive. "How can I burn fat without spending every waking moment exercising and dieting?"
He then told his audience about a "breakthrough," "magic," "holy grail," even "revolutionary" new fat buster. "I want you to write it down," America's doctor urged his audience with a serious and trustworthy stare. After carefully wrapping his lips around the exotic words "Garcinia cambogia," he added, sternly: "It may be the simple solution you've been looking for to bust your body fat for good."
In Dr. Oz's New York City studio, garcinia extract — or hydroxycitric acid found in fruits like purple mangosteen — sounded fantastic, a promising new tool for the battle against flab. Outside the Oprah-ordained doctor's sensational world of amazing new diets, there's no real debate about whether garcinia works: The best evidence is unequivocally against it.
The miracle cure isn't really a miracle at all. It's not even new. Garcinia cambogia has been studied as a weight-loss aid for more than 15 years. A 1998 randomized controlled trial looked at the effects of garcinia as a potential "antiobesity agent" in 135 people. The conclusion: The pills were no better than placebo for weight and fat loss.
More recently, a group of researchers summarized the evidence for this "breakthrough" extract in a systematic review of 12 randomized trials involving 706 participants. Some trials reported short-term slimming, but the overall effects were so small and most studies were so methodologically flawed that the authors were unable to conclude that garcinia extract has an impact on body weight.