"They are idolized by the public," Keith Ayoob, a registered dietician and director of the nutrition clinic at the Albert Einstein College of Medicine in New York, told ABCNews.com. "We hang on every word they say, whether it's good or not."
Celebrities swear by everything from macrobiotic diets to eliminating alcohol to skipping food altogether to get the weight off.
Kate Moss, that icon of uber-waif fashion, recently made headlines when she was quoted on the fashion Web site, WWD.com, as saying one of her mottos was "nothing tastes as good as skinny feels."
The phrase is commonly seen on pro-anorexia Web sites encouraging girls not to eat. Weight Watchers has used a similar slogan: "Nothing tastes as good as being thin feels."
Model Katie Green, who has campaigned the fashion industry to stop the use of super-skinny "size zero" models, told The Sun newspaper Moss' comments were "shocking and irresponsible."