I like the idea too. Throughout like, 99% of the game, it remains completely neutral concerning the player's weight gain. Then, all of sudden, in the Dizzy's facility, some of the descriptions mention the player character being scared.
And it's like, uhm... No? I'm stiff AF right now pal, not scared. With that in mind, I think the system could serve to be expanded by allowing you to essentially choose how your character feels in game about their weight and gaining/losing weight.
Such as perhaps, a system where you can be either neutral (basically the current text throughout the game where it describes, but never applies emotion), positive (where all the weight descriptions and pink text could be far more positively charged and potentially outright horny), and negative (where the player actively despises their weight gain. Basically the idea for this one is the "I just can't stop myself!" type of fat fetish story.)