This is an idea for those who are slave towards synthetic and unhealthy food and cannot control and keep up the diet.
Lets create a section where each unhealthy member posts their photos. And everyone around us, without lying(As usual we lie around when it comes to photos of eachother), post their comments on the members looks, motivate them "you can do it", you have it in you". "How many sets did you do today? Do one more. come on!!", "quit that junk, eat only what is suggested". "we are watching your moves!!". But also curse awfully, slang, fat , *** *** *** *** *** , your flabs are clinging, look at your lumpy legs, ohh those liquid filled cheek of yours, getting better but still something is hanging at your side, etc, etc, whatever. and then make the member take the diet seriously. Curse and slang them, plus motivate them to work out and diet, trap them so much that they even will not be able to say "I am what I am".
How is the idea?
Are you a masochist by the way?
No not Masochist, but ideas shall be taken form anywhere, that might work. :D