It seems like writers are looking for story ideas. This idea combines Weight Gain with the intoxication fetish. I think for me, they both appeal because of the decadence factor.
Anyway, the premise is this- some guys and girls (or a guy and girl, single girl) are shipwrecked on a mysterious island. This island has a "fountain of youth" that keeps everyone on the island young and healthy forever. The catch is, the fountain releases some kind of magical beer which causes the eternal youth, but it also very intoxicating and fattening. The story would be about the girl/girls/whoever encountering this society, and trying to resist it, but slowly succumbing to its temptations.
Anyway, the premise is this- some guys and girls (or a guy and girl, single girl) are shipwrecked on a mysterious island. This island has a "fountain of youth" that keeps everyone on the island young and healthy forever. The catch is, the fountain releases some kind of magical beer which causes the eternal youth, but it also very intoxicating and fattening. The story would be about the girl/girls/whoever encountering this society, and trying to resist it, but slowly succumbing to its temptations.