If you're looking to drop a few pounds, green tea may be able to provide just the boost you need. While the evidence regarding this supplement is conflicting, many sources agree that green tea pills, which contain two potential fat-burning substances, can promote at least modest weight loss. Green tea may work, in part, by boosting thermogenesis -- the production of body heat, which uses calories.
Green Tea Extract
Green tea, produced from the Camellia sinensis plant, can be prepared as a beverage or as an extract. One green tea extract in particular, known as epigallocatechin gallate or EGCG, is used in green tea tablets to promote weight loss. A study published in 2007 in the "Journal of the American College of Nutrition" concluded that EGCG alone has the potential to increase fat loss. MedlinePlus, however, has assigned green tea a rating of "insufficient evidence" for weight loss and notes that green tea does not help keep the weight off.
EGCG Plus Caffeine
Green tea also contains another compound often used for its potential to boost the metabolism and promote weight loss -- caffeine. A study published in 2005 in "Obesity Research" noted that a high caffeine intake, consumed through a green tea-caffeine mixture, was correlated with weight loss, by way of fat oxidation and thermogenesis. A 2009 meta-analysis published in the "International Journal of Obesity" reviewed 11 studies and also concluded that combining EGCG and caffeine did appear to produce a small but positive effect on both weight loss and weight maintenance.
Minimal Metabolism Boost
New York University Langone Medical Center notes that much of the evidence backing green tea as a weight-loss supplement is based on the idea that it can boost the metabolism and therefore cause the body to burn calories at a higher rate. The center concluded, however, that if green tea does in fact boost the metabolism, its effect is minimal. Overall, NYU Langone Medical Center states that there is little evidence supporting green tea as a weight-loss aid.
Adding Resistance Training
A study published in 2013 in the "Journal of Medicinal Food" found that drinking green tea alone caused a group of women to lose weight, body mass and waist circumference as well as maintain lean, or muscle, mass. But the greatest benefits were in the group that combined drinking green tea with resistance training. These participants saw an even greater loss of fat and waist circumference as well as lower triglycerides. And they simultaneously increased muscle mass and muscle strength.