Jennifer Sygo: Is Garcinia cambogia really weight loss in a bottle? Cutting through the Dr. Oz noise on a South Asian supplement
Have you heard of Garcinia cambogia?
If you haven’t, you probably will soon enough; or perhaps you’ve heard of it, but you don’t know what it’s all about. If you follow diet trends, or buy diet or weight loss products, however, then Garcinia combogia has likely already become part of your everyday vocabulary: This extract of a South Asian plant is hot stuff these days.
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For the past two years, I’ve been working on a book. The final product, titled Unmasking Superfoods, is now in wide release. While the road from concept to completion was long and at times daunting, I actually enjoyed the process more than I expected to, and the things I discovered changed the way I look at food.Throughout the process of writing, however, I found myself tempted to write in a loud and highly opinionated — some might call obnoxious — way a voice heard often in diet and nutrition books these days. Bestsellers tend to be full of sweeping generalizations, us-vs.-them thinking and, perhaps most irritatingly, cherry-picked research, all to support the author’s grand claim. There’s also the common theme that “this” is poison, or “that” is the reason we struggle with our weight — though “this” and “that” can vary with each book. It was hard to know where my way of thinking fit in.
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THE STORY
Garcinia cambogia is a plant found in India, Indonesia and other parts of South Asia that has a long history of use in cooking as a flavour agent in place of lemon or tamarind. More recently, Garcinia cambogia’s claim to fame stems from a compound found in the dried rind of its fruit, known as hydroxycitric acid, or HCA. First identified in the 1960s, HCA inhibits a particular enzyme, known as ATP-citrate-lyase, and early studies on cells and animals suggested it could prevent fat storage, reduce appetite, and ultimately, support weight loss efforts.
THE SCIENCE
The first well-controlled trial on Garcinia cambogia was published in 1998 in the prestigious Journal of the American Medical Association (JAMA), but the results were hardly sensational: in 84 overweight, but otherwise healthy men and women, half of whom were randomized to receive either two 500mg caplets of Garcinia cambogia 30 minutes before each of three meals per day (the caplets contained 50% HCA, providing a total of 1,500mg of the active compound per day), and half of whom received a placebo, or dummy pill, there was no significant difference in body weight or body fat between groups after 12 weeks. In fact, the placebo group actually lost nine pounds and 2.16% of body fat over the course of the study, while the Garcinia cambogia group lost seven pounds and 1.44% body fat, though the differences between the groups was small enough to be considered statistically insignificant.
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Importantly, while subjects were encouraged to follow a calorie-and fat-reduced diet, while maintaining their usual activity level, these elements of the study were not tightly controlled. While that means we didn’t necessarily gain insight in to the true effects of Garcinia cambogia alone, it does give a sense of how effective the supplement could be in a “real world” situation, and the results were hardly promising.
All told, among all placebo-controlled studies using HCA or Garcinia cambogia for at least eight weeks, six have demonstrated some benefit, while six have not. Of the six positive studies, only two used HCA or Garcinia cambogia on its own: the rest used weight-loss supplements that included other compounds, such as chromium or fibre, which could have influenced the results. In one of the two positive studies, published in 2000, overweight women given 2,400 mg of Garcinia cambogia (providing 1,200 mg of HCA) per day along with a low-calorie diet and exercise, lost 8.2 lbs over 12 weeks, versus 5.3 lbs for the placebo group. Interestingly, there was no difference in appetite markers between the groups, despite that being one of Garcinia cambogia’s possible methods of action. Also interesting was the fact that a small group of men initially included in the study had their results excluded because they showed no response to the supplement.
Of the six neutral studies, four examined HCA or Garcinia cambogia alone, with doses ranging from 1,000 to 1,500 mg per day of HCA. None found any effect on body weight or body fatness.
TAKING GARCINIA CAMBOGIA
If you do choose to take Garcinia cambogia, it is generally recommended that you do so between 30-60 minutes before each meal, however, some evidence suggests HCA levels take closer to between one and two hours to reach their peak, and that food present in the stomach suppresses its effect. So taking it on an empty stomach at least an hour before a meal is probably best. Recommended doses vary widely, but research studies typically use 1,000 mg to 2,400 mg of HCA per day, taken in divided doses over three meals.
‘You can’t trust most Garcinia labels, nor should you rely on suggested serving sizes’
As mentioned, Garcinia cambogia and HCA are commonly included in many weight loss products, often in combination with other stimulants, appetite suppressants or weight loss agents. Since being mentioned on The Dr. Oz Show in 2012, Garcinia supplements have exploded in popularity, leading to quality concerns. In late 2013, Consumer Labs, a consumer watchdog based out of the U.S., tested 13 Garcinia supplements, and found that only six contained the amount of HCA listed on the label.
Side effects, such as digestive upset and headache have been noted, but to date, Garcinia is generally considered safe, although studies in humans have only lasted up to 12 weeks.
THE BOTTOM LINE
“You can’t trust most Garcinia labels, nor should you rely on suggested serving sizes,” says Consumer Labs, and it’s hard to argue with the statement.
Garcinia might have some effect on weight loss, but to date, we have precious little high quality evidence in humans to prove the claims true. For my money, your best bet is still to focus on old-fashioned habits, such as a good, balanced diet and exercise, cooking and eating at home, and addressing mindless eating issues.
But that’s never quite as sexy as prescribing weight loss in a bottle, now is it?
-Jennifer Sygo, MSc., RD, is a registered dietitian and sports nutritionist at Cleveland Clinic Canada, and author of the newly released nutrition book Unmasking Superfoods, (HarperCollins, $19.99). Visit her on the Web at jennifersygo.com and send your comments and nutrition-related questions to her at info@jennifersygo.com.