Fill me up has a female protag that can gain weight and there are a good amount of girls in the story that will react and treat the MC differently as the stages and story progresses. Including berating, humiliation, and dialogue related to increase and change of weight.
Feeder Fantasy’s English translation + mods has maybe three or four Npcs that will react to the player with very limited dialogue at different player sizes. One NPC will encourage and feed the player if allowed so there is a bit of dialogue related to weight size there that would be the exception but it’s still more minor. Note I included the english Translation here as the original is by fallboy is in Japanese and has a male MC with character art. The translation changes the MC to female with no art and only sprites.