Research has suggested that green tea is less processed therefore it has a good concentration of polyphenols known as catechins. These catechins are the active agents to help in weight loss. Catechines are responsible to prevent the accumulation of fat in the body. These are the agents who increase the body temperature and burn the calories. Another study suggested that green tea also has some caffeine content which performs the duty of burning both calories and fat thus resulting in the reduction of weight. The office of dietary supplements has claimed that every 100 milligrams of caffeine burn extra 9 calories every time.
“Green tea reduces body fat accretion caused by high-fat diet in rats through β-adrenoceptor activation of thermogenesis in brown adipose tissue”; J.J. Chooco;THe Journal of Nutritional Biochemistry, November 2003Volume 14, Issue 11, Pages 671–676