It sounds like the thought of dating pushed your friend off her diet. After all, if one leads to the other, then it's not her decision to not date.

This is bogus, and part of the reality testing I believe you are advocating. I'm all for reality! You can only get rid of issues by facing them and recognizing them for what they are.

If you have emotional issues with weight, you must address that.

If weight is your excuse for other things (how can you expect ME to sky dive?) then that has to be addressed too.