Associations among Physical Activity, Diet, and Obesity Measures Change during Adolescence

Abstract

Background. Obesity in youth is highly prevalent. Physical activity and diet are influential in obesity development. However, there is a knowledge gap regarding links between activity and diet quality and their combined influence on obesity during adolescence. Objectives. We used five years of data from 2379 adolescent girls in the National Heart Lung and Blood Institute Growth and Health Study to evaluate the association between physical activity and diet quality during adolescence and to assess both as correlates of obesity. Design. Diet, activity, and body composition measures were evaluated pairwise for correlation. A canonical correlation analysis was used to evaluate relationships within and between variable groups. All statistics were examined for trends over time. Results. We found positive correlations between physical activity and diet quality that became stronger with age. Additionally we discovered an age-related decrease in association between obesity correlates and body composition. Conclusion. These results suggest that while health behaviors, like diet and activity, become more closely linked during growth, obesity becomes less influenced by health behaviors and other factors. This should motivate focus on juvenile obesity prevention capitalizing on the pliable framework for establishing healthy diet and physical activity patterns while impact on body composition is greatest.

Figure 1

Spearman's rho correlation coefficients. (a) Correlation between habitual physical activity and average energy density (ED) and dietary saturated fat percent (Sat fat %) by visit year. (b) Correlation between habitual physical activity and fiber intake by visit year. Correlation is significant (two-tailed t, P < 0.001) for years 5, 7, 8, and 10 for correlation with ED and fiber, and for years 7, 8, and 10 for correlation with Sat fat %.

Figure 2

Canonical correlation of physical activity and confounders with diet quality indicators by visit year. Physical activity and confounders: income category, race, maturation stage, height, weight, habitual physical activity questionnaire score (HAQ), 3-day activity diary score (3d AD), racial interaction HAQ, and racial interaction 3d AD; diet quality indicators: average energy density, average caloric intake, average dietary saturated fat percent, and average fiber intake. Lines represent stratified data from black (CCb) and white (CCw) girls and combined (CCc) data.

Figure 3

Canonical correlation between obesity correlates and body composition by visit year. Obesity correlates: income category, race, maturation stage, habitual physical activity questionnaire score (HAQ), 3-day activity diary score (3d AD), racial interaction HAQ, racial interaction 3d AD, average energy density, average caloric intake, average dietary saturated fat percent, and average fiber intake; body composition: BMI and body fat percent. Lines represent stratified data from black (CCb) and white (CCw) girls and combined (CCc) data.