In New York, the Council of Fashion Designers of America issued voluntary guidelines to raise awareness -- urging designers to promote the message that beauty is health -- but setting no minimum BMI requirement.
Officials in other key fashion capitals, London and Paris, did not act on the issue.
Designers say that clothes just look better on thin models and that the curves of more shapely models distract from the clothing they are showing off. They say rules and punishments would only stifle creativity.
Anorexia and bulimia, in particular, are complex diseases with physical, emotional and social roots. But a study by the British Medical Association confirmed the link between the images of "abnormally thin" models on TV and in magazines and the rise in anorexia and bulimia.
According to the Academy for Eating Disorders, 10 percent or more of late adolescent and adult women report symptoms of eating disorders at any one time. The AED says those who have such a powerful influence on the perception of beauty must take more responsibility.
Simon McGregor-Wood reported from Jerusalem, and Karen Mooney from New York.