During 1971-2000, the prevalence of obesity in the United States increased from 14.5% to 30.9%. Unhealthy diets and sedentary behaviors have been identified as the primary causes of deaths attributable to obesity. Evaluating trends in dietary intake is an important step in understanding the factors that contribute to the increase in obesity. To assess trends in intake of energy (i.e., kilocalories [kcals]), protein, carbohydrate, total fat, and saturated fat during 1971-2000, CDC analyzed data from four National Health and Nutrition Examination Surveys (NHANES): NHANES I (conducted during 1971-1974), NHANES II (1976-1980), NHANES III (1988-1994), and NHANES 1999-2000. This report summarizes the results of that analysis, which indicate that, during 1971--2000, mean energy intake in kcals increased, mean percentage of kcals from carbohydrate increased, and mean percentage of kcals from total fat and saturated fat decreased. An expert advisory committee appointed by the U.S. Department of Health and Human Services and the U.S. Department of Agriculture (USDA) is conducting a review of the Dietary Guidelines for Americans. Revised guidelines will be published in 2005.