The game already isn't realistic, and that's a good thing. There's no way in real life you're gonna hose feed someone for 250,000 calories. I think death is a fetish a lot of people (including myself) don't really want for a fun dating sim / sandbox feederism game.
I think toning it back to where health conditions serve as afflictions that limit a character is okay though. Especially towards the player, as it could definitely fuel a risk = reward type of deal. You eat with a girl, or girls, you get fat, and you have to manage your weight or afflictions. So, you're not entirely off, it's just a bit too extreme for the kind of game it is.