Models planning to strut down the catwalk during future Paris Fashion Weeks must make another walk – to the doctor's office – before slipping into their designer fashions.
The French Ministry of Social Affairs and Health announced that models must have a certificate from a doctor that says they're in good health, with much of the emphasis of "good health" centered on Body Mass Index, or BMI. The goal, they said, is "to protect the health of a category of the population particularly affected by this risk: models" as well as the public.
"Exposing young people to normative and unrealistic images of bodies leads to a sense of self-depreciation and poor self-esteem that can impact health-related behavior," said France's Minister of Social Affairs and Health, Marisol Touraine, in a statement, according to the BBC.
BMI – a measurement of the ratio between a person's height and weight – has long been used as a benchmark for health by categorizing people as underweight (a BMI of 18.5 or less), normal (BMI from 18.5 to 24.9), overweight (25.0 to 29.9) to obese (30.0 and higher). The average model has a BMI of 17.3, according to a study conducted by DreamModels.dk; the World Health Organization considers a person with a BMI of 17 to be severely malnourished.
The main problem with BMI, according to opponents, is that health isn't black and white – some people are medically healthy with a BMI of above 30 or under 18.5, while others in the normal range are considered unhealthy. It also doesn't take muscle mass or bone density into account, so some people with a large amount of muscle mass and very low body fat – like many professional athletes and bodybuilders – fall solidly into the obese category.
"I tend to use BMI or body mass index as a quick screening tool for health and a healthy weight," says Ryan Neinstein, M.D., a plastic surgeon based in New York City, adding that determining overall health "is something that just one number cannot do."
A 2016 study published in the International Journal of Obesity seems to back him up. For the study, researchers from UCLA evaluated data from most recent National Health and Nutrition Examination Survey to determine the link between BMI and other health markers, like blood pressure, cholesterol, glucose and triglyceride levels.
The researchers found that more than 30 percent of the people surveyed with a BMI in the normal range are actually unhealthy based on their other health markers, while about 15 percent with a BMI over 35 are considered healthy based on those same markers.
"This means that someone who eats well and exercises and has no family history of heart disease or cancer but is a two-pack-a-day smoker may be less healthy than someone we classically think of as overweight," says Dr. Neinstein.
Much of the health versus BMI debate is centered on those considered overweight or obese. However, those considered underweight by the BMI scale – like the models the French government want to keep off the runway – have a higher risk of dying than those with a BMI over 30, according to a 2014 study published in the Journal of Epidemiology and Public Health.
In the study, lead author Dr. Joel Ray, a physician-researcher at St. Michael's Hospital in Toronto, reviewed 50 previous studies to find the relationship between BMI and deaths (regardless of cause). He found that those with a BMI of 18.5 of less had a 1.8 times greater risk for dying than patients with a normal BMI.
The results are startling, but that doesn't mean being underweight predicts certain death.
"If we want to continue to use BMI in health care and public health initiatives, we must realize that a robust and healthy individual is someone who has a reasonable amount of body fat and also sufficient bone and muscle," Dr. Ray said in a press release at the time. "If our focus is more on the ills of excess body fat, then we need to replace BMI with a proper measure, like waist circumference."
Waist circumference, according to the U.S. Centers for Disease Control, measures the amount of fat a person around a person's abdominals, or the area around the stomach—the more fat, the more risk for developing conditions like Type 2 diabetes and coronary heart disease.
"Health risks really escalate when your waist is above 35 inches (women) and 40 inches (men), says Keith-Thomas Ayoob, Ed.D, R.D. FAND, an associate clinical professor in the Department of Pediatrics at Albert Einstein College of Medicine.
Ideally, women want to aim for a max of about 23 percent body fat, men 15 to 17 percent body fat, according to Dr. Ayoob, but adding that the important thing is how a person feels, not a certain weight. "I always draw the person's attention to how much better they feel, sleep, how much more energy they have, and all the positives that go with [reducing weight]," he says.
Time will tell if the ban will make a difference in the fashion industry as a whole. Some eating disorder activists applaud the move, saying that it won't fix all the problems, "but it will be one step closer to stemming the well-documented psychological harm these images cause, especially to young and vulnerable consumers," S. Bryn Austin, director of the Strategic Training Initiative for the Prevention of Eating Disorders at Harvard’s School of Public Health, told The New York Times.
But others are more skeptical.
"We don't want to reinforce the message that health can be determined by height and weight," Claire Mysko, Chief Executive Officer for the National Eating Disorder Association (NEDA), told ABC News.
"We think the spirit of it is in the right direction," she added.