Preliminary research suggests that oolong tea not only elevates your metabolism, it has a stronger fat-burning effect than green tea. Oolong tea comes from Camellia sinensis, the same plant that produces green, white and black tea. Oolong tea's effects on fat may stem from its antioxidants. In combination with moderate calorie restriction and exercise, oolong tea may help you fight belly fat. As with any supplement, consult your doctor before trying oolong tea.
Background
After harvest, growers bruise the tea leaves meant to become oolong tea, causing a release of some of the polyphenol oxidase in the leaves, according to the Linus Pauling Institute. Polyphenols are chemicals in plants that have antioxidant activity in the body. Leaves for oolong tea are oxidized more than green tea leaves and less than black tea leaves. Oolong tea may help with thermogenesis -- calorie burning -- and fat oxidation -- fat burning. In a Chinese study, most of the overweight and obese men and women who consumed 8 g of oolong tea daily for 6 weeks lost weight -- and their triglyceride and total cholesterol levels decreased significantly, researchers from China's Shenyang Pharmaceutical University reported in the February 2009 "Chinese Journal of Integrative Medicine."
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Most of the study subjects reduced their waist size as well as weight, suggesting that oolong tea may reduce belly fat. The Chinese researchers concluded that the oolong catechins -- polyphenols -- may be responsible for oolong tea's effects on fat. Earlier research on oolong tea also supports this theory. In a study on healthy young men, a daily allotment of full-strength oolong tea brewed from 15 g of tea resulted in a 2.9 percent increase in energy expenditure. Fat oxidation increased by 12 percent when the subjects consumed the full-strength oolong tea compared to 0 percent when they drank water containing an equivalent amount of caffeine, American and Japanese researchers reported in the 2001 "Journal of Nutrition."
Caffeine and Polyphenols
The American and Japanese research team theorizes that caffeine doses of 200 to 300 mg per day cause the maximal response in energy expenditure and that higher doses may not cause further elevation of the the metabolic rate above 3 percent to 7.2 percent during a 24-hour period. This study suggests that oolong tea's potential belly fat fighting powers come from its polyphenols, or the combination of polyphenols and caffeine, although further research is needed.
Metabolism
Drinking oolong tea increased energy expenditure by 10 percent in healthy young women compared to a 4 percent increase in energy expenditure after drinking green tea, researchers from Japan's University of Tokushima School of Medicine reported in the August 2003 issue of the "Journal of Medical Investigation." The oolong tea contained approximately half the caffeine and ECGC as the green tea, and double the polymerized polyphenols. The researchers concluded that oolong tea may increase metabolism with these polyphenols. Oolong tea's main polyphenols are theaflavin and thearubigin, rather than ECGC. Further research on how oolong tea promotes fat burning and its potential for fighting belly fat is required.
References
- Linus Pauling Institute; Micronutrient Information Center: Tea; Jane Higdon, Ph.D.; January 2005
- "International Journal of Obesity"; Thermogenic Ingredients and Body Weight Regulation; R. Hursel, et al.; April 2010
- "Chinese Journal of Integrative Medicine"; Beneficial Effects of Oolong Tea Consumption on Diet-Induced Overweight and Obese Subjects; R.R. He, et al.; February 2009
- "Journal of Nutrition"; Oolong Tea Increases Metabolic Rate and Fat Oxidation in Men; William Rumpler, et al.; November 2001
- "Journal of Medical Investigation"; Oolong Tea Increases Energy Metabolism in Japanese Female; T. Komatsu, et al.; August 2003
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