There is an idiotic new diet challenge sweeping the internet, and according to experts, it could be extremely dangerous.giphyThe "Cinderella weight" challenge, which started in Japan, is encouraging people to match their proportions to the supposed proportions of the animated Disney princess of the same name. "Cinderella weight" aims for a body mass index of 18, which is underweight according to the BMI scale.giphyIn order to determine your "Cinderella weight," you have to square your height in meters and then multiply that number by 18. For example, I am 130 pounds and 5'5". My BMI is 21.6 and considered "normal." If I were to achieve my "Cinderella weight," I would have to weigh in at about 110 pounds, which is technically underweight for someone my height.Yeah, I'll keep those 20 extra pounds, thankyouverymuch.Ironically, Lily James, who played Cinderella in the live-action version of the classic film, does not even meet the ridiculous standard. According to The New York Post, James stands at 5'7" and weighs 121 pounds. That gives her a BMI of 19, which is considered normal.giphyThankfully Twitter recognizes the harm of the challenge, and people have not been shy when it comes to calling it out as dangerous:Cinderella is a fairytale character. She's NOT REAL. So why on earth is anyone pandering to something totally unrealistic? Whoever came up with the ridiculous and irresponsible 'Cinderella Weight' idea has clearly starved themselves of their brain cells too. 👊— Lucy Horobin (@LucyHorobin) February 26, 2018 https://twitter.com/bellahrgrvs/status/968608819612971008https://twitter.com/GlitterSatan_/status/968898488267345921My "Cinderella" weight says I have to be 101 pounds to be a princess. 😂 https://t.co/msSsJuvhm4— Tabetha Wallace (@TabethaWatching) February 27, 2018 Of course, bodies come in all shapes and sizes, and some people will already meet the criteria of the Cinderella weight challenge without ever having to diet, but those who are actively trying to lose weight to match a fictional character's fictional proportions could be putting themselves at risk for an eating disorder if they turn to unhealthy methods to drop the pounds. Many experts claim that being underweight can be just as detrimental to your overall health as being overweight.So yeah, that doesn't sound like a fairytale to me.giphyBesides, Cinderella was probably only that thin because her stepmother wasn't feeding her enough! We are sure that once she moved in with the Prince, she was eating a much more balanced diet.