The types of exercise that you do are the secret to a slim waist. However it is very important to control your diet, because the diet will help you get rid of the fats in your belly. Still if you want to have a slim waist then you need to do the right exercises as well. At this point you should know that your waist size is determined mainly by your genetics. However you can have a slim waist if you by losing weight, exercising and choosing the right clothes.
You should also know that by doing crunches you will not get a slim waist and a flat stomach. The excess body fat that accumulates below the skin or around your organs is called a visceral fat. This fat can be removed with healthy diet and cardiovascular exercises.
If you want to flatten your stomach and define your waist, you should also add targeted ab-exercises. This routine will help you define and tone core muscles.