While antioxidants called Catechins present in green tea aid fat burning, boost metabolism and prevent fat accumulation, caffeine acts as a stimulant for improved exercise performance. Although promising for weight loss, weight loss depends on multiple factors. Some of these include the quality of green tea being consumed (which determines the quantity of weight loss aiding catechins), the time at which it is being consumed, the sweetners that are being added, the BMI of the person consuming the tea and pre-existing medical conditions. When a balanced diet and 30 minutes of physical activity per day is ensured along with green tea consumption, weight loss has often been observed. You should read about different types of tea to know more about their benefits and side effects or which tea is best for you.