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On a recent episode of "The Dr. Oz Show," green coffee bean extract — a supplement created from green (unroasted) coffee beans — was touted as a “fat burner that helps women lose weight.”
Oz tested the effects of the extract on 100 women. Half were given 400 mg of green coffee bean extract 30 minutes before breakfast, lunch, and dinner for two weeks; the other half were given a placebo. Participants were told to maintain their regular diets and to keep a food journal. The women who took the extract lost two pounds on average, while the placebo group lost an average of one pound
Since the episode aired, green coffee bean extract has become one of the most searched terms online. It's mostly available in pill form, but earlier this summer Starbucks added it as part of a new line of low-calorie drinks, which are being promoted as a “boost of natural energy.”
However, few published studies have examined the extract’s effects on weight loss — and none over the long term.
In a recent small, 22-week study, researchers gave 16 overweight adults low doses of green coffee bean extract (350 mg, twice a day), high doses of the supplement (350 mg, 3 times a day), or a placebo (3 times a day) for 6 weeks each with a 2-week break of not taking the pills between sequences. Subjects were encouraged to be physically active, but no dietary changes were recommended.
Results of the study, funded by Applied Food Sciences, Inc. (a company that manufactures green coffee bean extract) and published in the journal Diabetes, Metabolic Syndrome and Obesity, found that subjects who took the extract lost about 18 pounds on average — more than 10 percent of their body weight. No adverse side effects were noted.
Green coffee bean extract contains caffeine, a stimulant linked to weight loss. It also boasts high levels of chlorogenic acid, a polyphenol antioxidant that researchers speculate may promote weight loss by reducing the absorption of fat and glucose in the gut, and lowering insulin levels to improve metabolic function.
A 2011 review in the journal Gastroenterology Research and Practice found green coffee bean extract to lower body weight more significantly than a placebo in three studies. Although average weight loss —about 5.5 pounds — was moderate (perhaps because the doses were a modest 180 to 200 mg/day), researchers noted the poor quality of the studies and suggested more research before recommending the extract for weight loss.
While the extract appears safe, ingesting too much chlorogenic acid may raise heart disease risk since it elevate levels of the amino acid, homocysteine. In general, it's recommended that adult coffee drinkers stick to a moderate amount a day, about 3 or 4 cups, or 300-400 mgs.
But, despite the green coffee bean buzz, it's not worth shelling out money for weight loss, especially when results may be small -- the one extra pound lost by the extract group in the Oz study is barely even worth noting -- and long-term risks uncertain. Instead, stick to what we know helps with long-term weight loss: a sustainable, enjoyable diet paired with daily physical activity.
It's boring, but safe and effective.
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