Green tea has been an exciting supplement to watch unfold as more research continues to support its use in promoting health. Several studies have shown improvements in fat loss with regular use of green tea. The mechanism by which green tea works to shed body fat is complex and probably multi-factorial. However, one probable mode of action is on fat oxidation. The latest study from German researchers tested the effects of epigallocatechin gallate ( EGCG), the most abundant catechin in green tea, on carbohydrate and fat metabolism. Carbohydrate and fat oxidation rates was measured after the ingestion of 300 mg of EGCG or placebo in the fasted state and after a standard meal. Compared to placebo, supplementation with EGCG caused a shift in energy utilization from carbohydrate to fat oxidation. The effect was more pronounced after ingestion of the meal. In the placebo trial only 30% of the total energy burned after the meal was attributed to fat, whereas 54% of the energy burned came from fat oxidation after EGCG supplementation. These results show acute supplementation with 300 mg EGCG encourages use of fat over carbohydrate as fuel, which provides a plausible mechanism t explain the anti-obesity effects of green tea.

Boschmann M, Thielecke F. The effects of epigallocatechin-3-gallate on thermogenesis and fat oxidation in obese men: a pilot study. J Am Coll Nutr. 2007 Aug;26(4):389S-395S.