I posses big belly which is result of excess of carbohydrates, will it be useful if i take green tea to reduce my belly, or is it useless?

Eat less/exercise mo: Big belly is extra fat(energy) that you do not need. In order to get it under control, you need to reduce your energy intake especially fats/oils and fried foods. Eat ample amount of fruits and veggies and exercise daily. You will lose your fat belly slowly over 60-12 months. Drinking green tea all by itself would not help you much.