Although some Chinese weight loss herbs have earned reputations as being ineffective or dangerous---even deadly---there is one readily available at your local grocer or convenience store with proven fat-burning benefits: green tea. However, you should be aware that green tea contains caffeine, which may make its use inadvisable for some, and has not received Food and Drug Administration approval as a weight loss drug.
Green Tea Catechins
Green tea contains catechins, which are antioxidants. Dr. Michael Evans, a professor of family and community medicine at the University of Toronto, says green tea acts like a "rust buster" for your molecules, which limits the spread of free radicals that have been linked to many diseases, including heart disease and cancer. Green tea's role in weight loss is to burn fat and boost metabolism, and claims about green tea, which originated in China's Zhejiang Province, have been bolstered by clinical trials.
Green Tea and Mice
Fat rodents slimmed down and healthy weight rodents maintained their figures when green tea was included in their diets. M. Bose and colleagues at Rutgers University conducted several experiments involving mice and green tea. In a 2008 report published in the "Journal of Clinical Nutrition," the researchers concluded that the catechins in green tea helped reverse and prevent obesity. Despite eating a high-fat diet, obese mice lost a significant amount of weight and body fat when given green tea.
Product Labels
Green tea also helped men lose weight in a study conducted at the Center for Clinical Studies. Michael Boschmann and German researchers added 300 mg of catechins to the diets of some men and none to the diets of others. The men whose diets included catechins metabolized fat more quickly, according to 2007 findings published in the "Journal of the American College of Nutrition." Not all green tea contains the same amount of catechins. You can check products labels for catechins or EGCG, which stands for epigallocatechin gallate. To give you some examples, Stash Darjeeling Organic Green Tea contains 100 mg of catechins per tea bag and Lipton's 100% Natural Green Tea contains 29. The amount of catechins in green tea capsules also varies. Green Tea Slim capsules, for example, contain 60 mg of catechins, two-thirds the amount of catechins provided in Meta-T Green Tea capsules.
Black Tea vs. Green Tea
Black tea also contains catechins but in much smaller quantities than in green tea, which undergoes less processing. The high number of catechins in green tea was linked to greater weight loss in men by Kevin Maki, of Indiana's Provident Clinical Research, led an experiment in which some men were asked to drink black tea containing 22 mg of catechins of green tea containing 660 mg and to follow a reduced-calorie diet for three months. The men who drank green tea lost nearly twice as much weight---5.3 pounds compared to 2.9 pounds---than the men who drank black tea. Maki and colleagues, who reported their findings in the "American Journal of Clinical Nutrition," said the catechins increased metabolism and decreased body fat.
Safety Concerns
Most of the safety concerns about green tea are linked to its caffeine content. The amount of caffeine varies by brand and even within brands, but it should be listed on the label. Caffeine may lower babies' birth weights, according to a report published in the "British Medical Journal," which cautioned pregnant women against ingesting more than 100 mg of caffeine daily. The FDA also issued a warning in September 2010 to green tea manufacturers who made health claims on their product labels. The FDA said Canada Dry Sparkling Green Tea should not claim that the beverage is enhanced with antioxidants because it is a snack food that cannot legally make nutritional claims. The FDA also warned Lipton against making claims that its Lipton Green Tea 100% Naturally Decaffeinated might protect against heart disease.
References
- "Biotech Business Week"; Scientists at Rutgers University Publish New Data on Obesity;(NO AUTHOR)Oct. 13 2008
- "Drug Week", Obesity and Diabetes: Researchers For Clinical Research Report Details of New Studies and Findings in the Area of Obesity and Diabetes; (NO AUTHOR)Oct. 26 2007
- "Biotech Business Week"; Obesity; New Obesity Study Findings Have Been Reported by K.D. Maki and Colleagues; March 2 2009
- BMJ.com: Maternal Caffeine Intake During Pregnancy and Risk of Fetal Growth Restriction; a Large Prospective Observational Study
- Amazing Green Tea: Green Tea Brands
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