If you want to drink green tea to lose weight, you'll be happy to know that science supports the hype. Green tea contains chemicals that boost metabolism and may help protect against disease. White tea hasn't been studied as extensively as green tea, but it contains the same compounds in higher amounts so should have similar or greater benefits. The caffeine in green and white tea may adversely affect some individuals.
How Tea Gets its Colors
According to "The Washington Post," all tea comes from the same plant--camellia sinensis--and the color of tea depends on its level of oxidation. The more oxidation, the darker the color. Black tea is fully oxidized and oolong tea, a brown tea, is partially oxidized. Green tea is treated with hot steam when it's picked, a process that deactivates oxidation. White tea comes from the bud of the tea plant before chlorophyll turns it green. Like green tea, it is steamed. White tea and green tea contain the same antioxidants, but white tea has more, according to Demetre Whitmore, an oncology nutrition specialist at the Washington Cancer Institute at the Washington Hospital Center in Northwest.
Catechins in Tea
The metabolism-boosting chemicals in green and white tea are called catechins. Both oxidation and processing--packing tea into bags, bottling it as drinks--affects the number of catechins in your tea and its effectiveness as a weight loss supplement. You can check the labels for the number of catchins, epigallocatechin gallate or EGCG, contained in a serving of green or white tea. If you brew loose tea at home, a cup of green tea will contain about 127 milligrams of catechins, more than twice as many as oolong tea and four times as many as black tea, according to the U.S. Department of Agriculture. If you purchase tea bags or bottled green tea, the number of catechins may be significantly lower. Stash Darjeeling Organic Green Tea contains about 100 milligrams of catechins, but Celestial Seasonings Green Tea contains only 19. White tea contains more catechins and less caffeine than green tea.
Green Tea and Weight Loss
Several studies support claims that catechins affect weight loss. Kevin Maki, of Provident Clinical Research, compared the effects of green and black tea on weight loss. Some men in the study drank black tea containing 22 milligrams of catechins and some drank green tea containing 660 milligrams—the amount in about six cups. According to the study, reported in 2009 in the American Journal of Clinical Nutrition, men who consumed the high amounts of catechins lost nearly twice as much weight--5.3 compared to 2.9 pounds--and experienced greater losses in waist size and body mass index.
Michael Boshmann and other researchers at the Center for Clinical Studies found that men who consumed 300 miligrams of catechins daily--about three cups of green tea--metabolized fat more quickly than men given a placebo. Boschmann, who reported his findings in 2007 in the "Journal of the American College of Nutrition," said his results were promising but that more research was needed. M. Bose and other scientists at Rutgers University also found that green tea helped obese mice lose weight and rodents of normal weight retain their shapes, according to the study published in 2008 in the "Journal of Clinical Nutrition."
Green and white tea may also protect you from some diseases, Whitmore says. She says the polyphenols in the tea protect against prostate cancer and that their antioxidants can reverse damage caused by free radicals in the body. Polyphenols may also prevent blood clotting and lower cholesterol, Whitmore says. If you are pregnant, nursing or have been advised by your doctor against caffeine consumption, you should seek medical advice before adding green or white tea to your diet.