During the past 20 years, adult obesity rates have doubled in the United States. The National Institutes of Health (NIH) issued guidelines in 1998 recommending that healthcare professionals advise obese patients to lose weight. We examined trends in physician counseling for weight loss during 1994-2000, characteristics of obese adults receiving advice to lose weight in 2000, and the association in 2000 between receiving advice and attempting to lose weight.