- Green tea contains caffeine, which speeds up the metabolism and breaks down fat. While the fat-burning properties of caffeine are generally harnessed only by exercise, caffeine keeps blood sugar at higher levels than normal and thus reduces hunger, which could also be considered pre-emptive fat burning. Still, as with any caffeine-based product, the best way to harness the fat-burning potential of green tea is to take it with lots of exercise.
- Green tea contains catechin polyphenols, which like caffeine tend to increase the body's thermogenic activity--the increased consumption of calories as energy. This increased caloric usage can also result in more fat-burning. As with the caffeine, the effects of this increased thermogenesis are most pronounced when the consumption of green tea is paired with exercise, although drinking green tea alone is still better than nothing.
- A study on Japanese men showed that green tea extract (as compared with pure caffeine or a placebo) resulted in a 4 percent increase in metabolism when paired with exercise. Three cups a day of green tea provides a sufficient quantity of polyphenols and caffeine to stimulate the body's natural fat-burning propensities and makes exercise slightly more effective at burning fat.
