It will depend on the type of coffee that you are going to drink. It is the caffeine in coffee that can work as a natural appetite suppressant. It is also known to boost metabolism so you will be able to get rid of some excess fat in an easier manner.
Just remember that while drinking coffee can help you lessen your appetite, it will still depend on the food that you eat and the exercises that you will do if you would begin to lose weight. There are also moments when coffee could cause weight gain especially if you put in too much sugar, too much milk, and too many sweeteners on your drink.