If you measure green tea by antioxidants, you need 300mg to 660mg of green tea antioxidants daily to achieve clinically proven weight loss. But if you measure green tea for weight loss by serving size, it can vary from three to 55 cups, depending on the brand and type of green tea you consume.
Green Tea Compared to Exercise for Weight Loss
In large doses, drinking green tea may burn as many calories as walking for 30 minutes a day. In a study conducted by Kevin Maki and other U,S. scientists, men who drank green tea containing 660mg of catechins --- the antioxidants in green tea --- lost 2.5 lbs. more in 12 weeks than men who drank black tea containing 22mg. To lose the same amount of weight through exercise, you could walk 30 minutes daily for 12 weeks at a 2 mph pace.
Green Tea May Reduce Abdominal Fat
The green tea drinkers in Maki's study, published in 2009 in the "American Journal of Clinical Nutrition," lost 5.4 lbs. in 12 weeks, but some of that weight loss was achieved by following a calorie-restricted diet. The men who also reduced calories but drank black tea lost 2.9 lbs. The green tea drinkers lost considerably more abdominal fat than those who drank black tea.
Green Tea Catechins
If you wanted to reach for the results achieved in Maki's study, you would need to drink 5.5 cups of green tea brewed from loose leaves, according to figures from the U.S. Department of Agriculture. You could also drink about 6.5 cups---the USDA used a 6 oz. measure for a cup of tea --- of green tea brewed from plain tea bags. The amount of catechins in green tea is much lower in flavored, decaffeinated and bottled green teas. You would need to drink nearly 12 cups of decaffeinated green tea, slightly more than 15 cups of flavored green tea and 55 bottles of commercial iced green tea, according to USDA figures. Catechin content varies considerably by both brand and type. One brand of organic green tea bags, for instance, contains 100mg of catechins --- the average in the USDA study --- while another brand contains 19mg.
Weight Loss Without Dieting
Some weight loss studies demonstrated weight loss results with lower catechin levels. A study led by German researcher M. Boschmann found that consuming 300mg of green tea catechins daily resulted in weight loss, according to a report in October 2007 in the "Journal of the American College of Nutrition." In another study at Rutgers University, M. Bose and others found that obese rodents fed green tea catechins lost weight and healthy weight rodents didn't gain weight when their diets included green tea catechins, according to Bose's report published in October 2008 in the "Journal of Nutrition." In the Boschmann and Bose studies, participants---people and rodents---lost weight without changing their diets.
Reducing Calories Yields Better Results
Green tea consumption does not compare to dieting for weight loss results. The men in Maki's study attributed one-quarter of a pound weekly to drinking six cups of green tea daily. You could lose that much by substituting mustard for mayonnaise on turkey sandwiches. And a moderate reduction of calories --- 500 a day --- could yield a 1 lb. weight loss weekly, four times as much as by drinking green tea.
References
- "Biotech Business Week"; New Obesity Study Findings Have Been Reported by K.D. Maki and Colleagues; March 2 2009
- Mayo Clinic: Exercise for Weight Loss
- "Drug Week"; Researchers from Center for Clinical Research Report Details of New Studies and Findings in the Area of Obesity and Diabetes: Oct. 26 2007
- USDA: Brewing Up the Latest Tea Research
- Amazing Green Tea: Green Tea Brands What Catechins Levels
- "Biotech Business Week"; Scientists at Rutgers University publish new data on obesity; Bose, M., etal; Oct. 13, 2008
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