Crunches do burn belly fat, but only in combination with cardiovascular exercise and a clean diet. You cannot spot train by doing crunches alone.
Many people believe that if they do a thousand or more crunches a day they are going to achieve a six-pack to die for. This is truly not the case. While crunches do build and tone muscle, the only way to achieve the washboard stomach is through diet and exercise. In fact, it the food you consume that will make or break your six-pack.
A clean diet that is needed to shed excess fat on your belly should consist of lean protein sources, such as chicken or fish, and lots of fruits and vegetables. The carbohydrates that you consume should not be refined, and there should not be any processed food in your diet. It is best to stick to raw and fresh food that is natural and contains little to no preservatives.
A clean diet combined with regular cardio and weight training will get rid of the belly fat and cause your abs to shine. Crunches should be a supplemental exercise that you incorporate with an already strong routine.
Remember, crunches do burn belly fat, but only in combination with a clean diet and lots of cardio. Spot training is a myth and should be avoided if you want to shed belly fat.