David Beckham is a bitch. If you want to feel good instead of just looking good then you should consider eating a balanced diet, weight training and playing some team sports. Any form of exercise that involves interacting with opponents is always going to build muscle and increase your metabolism faster than ones that don't. They also build coordination and sharpen reflexes. It also exhausts you that much faster.Try running a mile or two one day, then playing a game of basketball or two the next. Or maybe take some Taekwondo lessons. See how you feel after each one. There ain't nothing for free in the real world.