Individual and environmental factors associated with snack characteristics among adolescents in the United States of America: analysis of the National Health and Nutrition Examination Survey 2011–2018

Adolescence is characterised by a decrease in diet quality and higher intakes of energy-dense nutrient-poor foods at snacks. Snacking is almost universal and makes a significant contribution to total energy intake among adolescents (1) . Evidence suggests adolescent dietary intake is influenced by individual and social and physical environmental factors (2) . However, the relationships between adolescent snacking with individual and environmental factors remain largely unexplored. This study aimed to investigate the individual, social and physical environmental factors associated with snack characteristics in a nationally representative sample of adolescents in the US. This secondary analysis used 24-hour dietary recall data collected during 2011–2018 from the National Health and Nutrition Examination Survey (1,835 boys and 1,796 girls aged 12–19 years). Snacks were defined based on participant-identified eating occasions; along with where they were sourced from and location of consumption (3) . The associations between snack energy density (ED; kJ/g) and food groups consumed at snacks (vegetables, fruits, refined grains, whole grains, protein foods, dairy, and snacks and sweets) with individual (age, race and ethnicity), social-environmental (socioeconomic position, food insecurity), and physical environmental (snacking location and source of snacks) factors were examined using a multilevel two-part (logistic and linear regression) models, stratified by sex. We found associations for snack ED and food groups consumed at snacks with the source of snacks. Snacks obtained from convenience stores, vending machines, and social sources (from someone else) were more energy dense than those from grocery stores. Additionally, adolescents had lower odds of consuming fruit at snacks obtained from convenience stores (OR (95% CI): Boys, 0.20 [0.12, 0.33]; Girls, 0.31 [0.16, 0.61]) and vending machines (OR (95% CI): Girls, 0.07 [0.01, 0.56]). There were also lower odds of consumption of dairy foods at snacks outside the home (OR (95% CI): Boys, 0.69 [0.55, 0.88]; Girls, 0.70 [0.53, 0.92]). Non-Hispanic black girls consumed significantly fewer dairy foods as snacks compared to non-Hispanic white girls (β (95% CI): −0.37 [−0.60, −0.14]). Few associations with snack ED and food groups were observed for individual and social-environmental factors; non-Hispanic black girls showed lower dairy consumption at snacks. Among US adolescents, snack ED and food groups consumed at snacks were associated with the source of snacks. However, few associations were found for socioeconomic position, food insecurity, and snack consumption location. These findings suggest that public health interventions targeting the sources of adolescent snacks may encourage healthier food choices. Further studies on adolescent snacking should explore other individual and social-environmental factors such as food preference and influence of peers and family, and these studies should examine a wider variety of consumption locations outside the home.