I think that it wil pass if you don`t talk that much for now and afterwards you talk like nothing and don`t mentionn it it will be o.k

Another way is what RackBottom said - to be hinest...maybe be nice too. ask how is your friend...etc.

Now - you don`t have to tell him it`s triggering or doing anyhting to your self asteem but asking kindly NOT to call you anorexic or whatever doesn`t look that strange!

he violated the very basic rules of polite behavior, so...you CAn say that you are not exactly comfortable with such words, and it`s not a must to explan everything to everybody.