When I was at Anime Fest, one panelist (I think it was Blake Shepard, but I am not entirely sure ;_; Sorry panelist!) said that it’s related to Japanese’s culture stress on politeness. He said that Japanese people don’t like taking up too much space because it’s rude to other people. On the other hand, in the article “Being Fat in Japan,” Laguna Levine (2014) explains that being overweight and “[taking] up a lot of room in stores will get you dirty looks from strangers, especially if your butt knocks something off a rack.” So, I think that this could very well be a reason why Japanese people want to be slim.

But the girls in anime that diet are usually very thin. I mean, look at this picture of Honoka from Love Live. In this scene, her mom and sister were freaking out over her gaining “a ton” of weight. But look at her! She is perfectly fine and is beautiful the way she is. And yet everyone gets on her case about losing all the weight she supposedly gained.