The coffee is known to be effective for diet. The coffee is a low-calory drink so if fat people have coffee black, it is good to drink. If we get coffee with caffeine and take proper exercise, it burns fats with priority. So the coffee is a help to be more effective when we take aerobic exercise. However, the coffee only help to burn fats well. So actually to burn fats is aerobic exercise. Doing exercise is the best way to lose weight, but a cup of coffee is a good partner both during and after the exercise session.