On Dec. 11, celebutante Nicole Richie was arrested for driving under the influence after she was spotted driving the wrong way on a Los Angeles freeway. According to the booking sheet, the 25-year-old star of ''The Simple Life'' is 5-feet-1 and 85 pounds.

By coincidence the next day, designer Diane von Furstenberg, in her capacity as president of the Council of Fashion Designers of America, sent the organization's members a letter urging them to take a position on the issue of underweight models. Her letter followed a meeting last week of industry leaders such as Vogue editor Anna Wintour, designers Derek Lam and Vera Wang, and health and nutrition experts.

The letter called dangerously thin models a ''global fashion issue.'' Further, Von Furstenberg wrote that ''as designers, we cannot ignore the impact fashion has on body image. We share a responsibility to protect women, and very young girls in particular, within the industry, sending the message that health is beauty.''

Forty years after the Twiggy era, critics might say that message is coming a little too late. Thinness has become so deeply ingrained in our food-obsessed culture that the ultra-thin standards of beauty have infiltrated the psyche of nearly every public and private figure, whether a teenage model or a red-carpet strolling actress.

At the extreme, a preoccupation with weight leads to eating disorders, which now affect nearly 7 million women and 1 million men, an epidemic level according to the National Association of Anorexia Nervosa and Associated Disorders of Highland Park, Ill.

Alarming recent events have put the gaunt under increased scrutiny. In August, a model in Uruguay collapsed on the runway and died of heart failure, possibly from being underweight. In September, the organizers of fashion week in Madrid, Spain, issued the world's first catwalk ban on models who didn't meet a minimum body mass ratio of 18, a number calculated on height and weight that would exclude Kate Moss. In November, a 21-year-old Brazilian model, Ana Carolina Reston, died in a Sao Paulo hospital from complications of anorexia. She was 5 feet 8 and weighed 88 pounds. Brazil has joined the campaign to create guidelines.

After initially refusing to follow Madrid's standards, representatives of the Italian government and its fashion trade group, the Camera Nazionale della Moda, said last week that they would establish minimums for the weight and age of models. The rules would take effect with February's shows, making Milan the first fashion capital to embrace such guidelines. Fashion houses that don't abide might be prevented from showing.

Von Furstenberg said it's important that the American industry join the dialogue: ''We have an opportunity to help, and I think we have to seize that opportunity.''

Richie's well-publicized shrinking frame has again caused concern that she has become an unhealthy fashion role model, particularly since she has become ubiquitous in style and celebrity magazines and television shows.

This week, the anorexia association began drafting a news release that will encourage the United States fashion industry to acknowledge its responsibility in promoting ultra-thinness and take a leadership role to prevent abuses, said spokesman Keith Sanderson.

''We're urging those in the industry to think before they glamorize the ultra-thin,'' he said. ''Anorexia nervosa kills. No other mental illness matches eating disorders for killing you.''

Michael Strober, director of the Eating Disorders Program at the Resnick Neuropsychiatric Hospital at the University of California, Los Angeles, warned against linking fashion or celebrity imagery with anorexia. The disease has many complex causes, including genetics. And there is no proven link between the disease and the effect of fashion or the media.

''I don't think you can assume that there will be a dramatic protective effect if the fashion industry alters its standard of the body aesthetic,'' he said. Still, Strober called the measures ''a useful step forward because it calls attention to the issue.''

In questions of weight, it's an ever-losing game. Celebrities are bashed for being ''fat'' - think Mariah Carey or Alicia Silverstone - when they may still be pounds thinner than the average American. When they reduce, they're criticized for being too thin.

''Showbiz Tonight,'' on CNN Headline News, has a twice-weekly feature on Hollywood's obsession with weight and body image. Regular cover stories on mainstream magazines such as People and US Weekly intensely scrutinize every curve or bump. In recent months, People's cover headlines have screamed: ''Kate's Body After Baby,'' ''Shockingly Thin,'' ''How Kirstie Lost 71 Lbs.'' and ''American Idol's Katharine McPhee: 'My Battle With Bulimia.' ''

There are encouraging signs that the fashion and entertainment industries could be getting past their thin obsessions. Just look at the curvy Jennifers - Lopez, Garner and ''Dreamgirls'' newcomer Hudson - who return the definition of femininity to its sensuous and assertive origins. It's a message that could go a long way, said Von Furstenberg.

''I always think it's a good idea to promote health,'' she said. ''I believe in strong women.''