You know, comments like that can hurt others as well as yourself. I'm the wrong person to talk to about that. Exercise is best when it's enjoyable and fun. Too much exercise puts stress on the muscles and immune system. Another way to respond to a comment about weight or eating is to turn the comment into a question that reveals the underlying assumption.
Many people use the expressions quoted above without thinking of their implications.
But if we want our environment and actions to reflect our real values, rather than just outer appearances, we need to reevaluate what we say and how we judge others. Instead, learn to be a support to yourself and your friends, with the things that really matter. If anyone makes you feel uncomfortable, it's up to them to change, not you. Stand tall and relax. Move around, remembering to breathe deeply without slumping.