The U.S. government says any BMI of less than 18.5 indicates someone is underweight, though not necessarily suffering from an eating disorder. The New York Times lists models like Gisele Bundchen and Naomi Campbell as being in the 16 to 17 range, while the particularly wispy Kate Moss’s BMI registered at about 15 in her modeling heyday. For a woman who stands 5-foot-2, a BMI of about 18 would require weighing about 100 pounds.

All the right people seem to hate the law. The fashion industry has tended to oppose such restrictions. Designers like Karl Lagerfeld have claimed, risibly, to have never worked with anorexic models. The law may have some effect on the health of models, and it’s hard to disagree with the motivation involved. From thigh gaps to photoshops, it’s easy to see dangerously unrealistic expectations in the industry. Campaigners cite the case of Isabelle Caro, a former model who died of anorexia in 2007 and at one point weighed as little as 55 pounds.

But will this law achieve its broader goal of combatting anorexia? Or, to put that another way, can you legislate people out of disease?