This is not good. If he was right and if he was your mother, maybe it would be good. But he your boyfriend and he is wrong.

He is supposed to make you stronger. If there is actually something wrong with the way you eat and he is concerned, he does something that helps you eat healthier. We always want to try to eat healthier. So if we have a partner that somehow makes it more fun for us to eat healthier, that is good. But it shouldn't be about pressuring or shaming someone into being more healthy.