Gaining

It won't work--you can temporarily delude people with hypnosis, but you can't make them do something they normally wouldn't do. You can't make them murderers for example.

But even if you could do it, you're right: it's completely unethical. It's her body, and her decision to gain or not to.

If it really means that much to you then you two need to split... Enough said. I mean, you can try to wait it out and see where it goes, but if it means so much to where you wanna do hyposis on her (creepy), then don't try to change the person... find someone who IS that person.

P.s.
a runner that only runs twice a week? Weeeeaaak