>>712348274Needs more of a gimmick.
"A young man (you) stumbles onto an old shrine and breaks something. This unleashes a spirit of gluttony that will annoy you for eternity by turning everything you try to eat into foods you hate... UNLESS you help him get revenge on the descendants on those who sealed him away 100 years ago by making them become fatties."
You have a bunch of food based powers and have to make sure the girls encounter the right food, in the right way and at the right time to fatten them up. Give the gym girl something that will make exercise harder, give the rich girl something basic and common she would never normally consider, give the shrine maiden her childhood food and so on.
Then have "reward" scenes that let you use your powers to push a leap in size. Finish this milkshake to win PRIZE except its magically never ending, a scenario with the condition "I will try one of everything at this buffet" but every return trip gets increasingly absurd and impossible with new lavish foods, some kind of food truck accident and she has to EAT her way out.