Of course its a money making industry, every business is. Gym's /Dance classes etc are only in it for the money, not for the individual. If you think about it, it's easy enough to go for a 'free' jog or walk, or do exercise in your own home. But people go to these places for the social side, or encouragement or the 'push' they need as they can't do it themselves at home. Its the same for diet classes, some need the encouragement others don't and are quite happy to do it themselves. Every diet class, gym, dance class or other is 'worth their weight' if it does the job it's intended to do and the participating person is happy to go.