When Katsuki came over to his boyfriends house to stay over for dinner he couldn't help but notice the things inko said. Inko was your mother but she would say things to fat shame izuku, when he was already really skinny

Katsuki knew Izuku wasn't like obsessing over food plus izuku was a pretty healthy person but inko made it sound like he ate 24/7. Izuku was very insecure so that didn't help at all. During dinner inko was so sweet to Katsuki while Izuku was just eating in silence