Are adolescents' perceptions of dietary practices associated with their dietary behaviors?

Despite interventions designed to change behavior, many adolescents continue to consume unhealthy foods. Dietary patterns are important for disease prevention, making it necessary to understand the reasons for these poor choices. This cross-sectional study explored the relationship between perception of dietary practices and dietary behaviors among adolescents. Participants (n=15,283; mean age=15 years; 50.7% female) completed the 2004-2005 Texas School Physical Activity and Nutrition survey. Perception of dietary practices included fat content of foods usually eaten and healthiness of usual eating habits. Dietary behavior was measured by self-report of foods eaten the day before survey administration. Composite scores of unhealthy and healthy eating were created. Regression analyses examined whether perception of dietary practices was consistent with actual dietary behavior, controlling for sex, grade, and race/ethnicity, and accounting for the complex sampling design. Higher perceived fat content was associated with increased consumption of unhealthy foods, while higher perceived healthiness of eating was associated with increased consumption of healthy foods. For perceived fat content, the difference in the Healthy Eating Index between extreme categories was 26% (P<0.001), while the difference in the Unhealthy Eating Index between extreme categories was 81% (P<0.001). For perceived healthiness, the difference in the Healthy Eating Index between extreme categories was 23% (P<0.001), while the difference for the Unhealthy Eating Index was 44% (P<0.001). Self-perceptions of dietary practices were significantly associated with dietary behaviors, indicating awareness about the relative nutrient content of foods consumed. Interventions that move beyond dietary knowledge and create changes in the social and physical environment are needed.