Another study suggested the increase in calorie output was equal to about 100 calories over a 24-hour period. You don’t need to drink a lot of green tea to help you lose weight. While weight loss benefits vary based on different dynamics, they have been found by drinking as little as 2.5 cups of green tea per day.nother study suggested the increase in calorie output was equal to about 100 calories over a 24-hour period. You don’t need to drink a lot of green tea to help you lose weight. While weight loss benefits vary based on different dynamics, they have been found by drinking as little as 2.5 cups of green tea per day.