Well, first of all I would recommend forgetting about your classmates. You should definitely be doing this for YOU. Motivations like pleasing other people come and go and aren't really reliable...at least in my experience.

Perhaps you can assess why it is you are failing, like you say. Are you getting bored with the foods, or perhaps find yourself lacking time to prepare them? Is it exercise that's your downfall? I think you should make a list of all the reasons why you quit and find a way to solve those problems.

Good luck!