I agree with what you and TotsMclegit said. To be honest, I don’t really like when on some games and mods make it so that the player gets heavily punished for getting fatter. In some ocassions I get is for “realism” or similar, but it also discourages the player for attempting to use the fetish content in your fetish game/mod.
There is also a case of extremes, in some games where characters can gain or lose weight, there is no reason to not get fatter, while in other, getting fatter must be avoided at all cost to not suffer from their penalties.
I don’t think that getting fat shouldn’t give penalties to the player, but it should give a reason as to why you want to get fatter. Dungeon of the devourer by glaciepuff is a good example on how to use weight as a mechanic. I think Roundbound is also like that, but i haven’t played that game in a long time.