It really comes down to practice. Most professional chefs and most TV chefs have spent dozens, if not hundreds, of hours preparing foods while learning and working their way up in the industry.
While it looks flashy and impressive on TV, it really comes down to practical requirements of preparing food on a line or in a professional kitchen. They learn to cut and chop fast out of necessity, rather than merely to look good doing it. Much like any craftsman or artist, they have practiced extensively to be as good as they are.