No, not necessarily. You do have to cut down on food consumption to an extent, but don't have to specifically fast. The last thing that you want to do is to go on a crash diet as this can lead to a wide range of problems. Make sure that you stick to a good diet plan that includes lots of proteins and very less fat. Avoid eating food items such as cheese, butter and other dairy products. Avoid fasting as this can lead to acidity build up in the stomach and cause even more problems. All you need to do is to tweak your diet a little