['Little is known about behaviors associated with successful weight loss during adolescence. The first objective of the current study was to identify meaningful weight loss, weight maintenance, and weight gain in male and female adolescents. The second objective of this study was to apply these methods to U.S. adolescents from the National Health and Nutrition Survey 1999 to 2002 data and to identify factors associated with these weight change outcomes.', 'The current analyses include 1726 (female, 836; male, 890) 16- to 18-year-old adolescents who completed the questionnaire components and interview for either the 1999-2000 or the 2001-2002 National Health and Nutrition Survey study. Dietary intake, physical activity, and dieting attitudes were compared across the weight loss (L), maintain (M), and gain (G) groups in the entire sample and in a subset of adolescents who are overweight and at-risk-for-overweight (> or = 85th percentile).', 'The tested method for identifying weight L, M, and G groups has both theoretical and statistical validity and, when applied to the sample, showed the expected direction of changes in weight. Results suggest that more overall physical activity, more vigorous exercise, and less sedentary activity are associated with being in the L group in both the full sample and the overweight and at-risk-for-overweight sample. In addition, fewer teens in the L groups endorsed efforts at trying to lose weight, compared with the M and G groups.'] Does identification and correlate of weight loss in adolescents in a national sample?