Green tea contains the natural lipase inhibitor that have been found to inactivate gastric and pancreatic lipases. For fat and oil to be absorbed in our body ( after we eat any food that contains fats and oil such as burger and hotdog), it needs to be broken down in to smaller molecules by lipase enzymes in our stomach and small intestines.
The more fat and oil in our diet, the more it will broken down, absorbed and store away in our body, resulting in weight gain and obesity. The natural lipases inhibitiors in green tea will attach themselves to lipases, preventing them from breaking down some of them from breaking down some of the oil that we have eaten.This cause the dietary oil remain as large particles. Since, undigested oil cannot be absorbed, it stays in the intestines, until it is finally flushed out of the body through normal bowel movement.