Cross-sectional associations between lunch-type consumed on a school day and British adolescents' overall diet quality.

Diet quality of children consuming school meals tends to be better than that of children consuming packed lunches (from home) or food bought outside school. This study investigates the association between different types of lunch consumed in a school day and diet quality of UK adolescents. A total of 2118 British adolescents were included from the National Diet and Nutrition Survey (Years 1-8; between 2008 and 2016). All participants attended school and were aged 11-18 years with valid 3 or 4-day diary records and the analyses were stratified by age group (11-14 and 15-18 years). The Diet Quality Index for Adolescents (DQI-A) tool consisting of three components; diet quality, diversity and equilibrium, was used to assess adherence to dietary recommendations. Overall DQI-A scores range from -33 to 100%. Overall mean DQI-A score for all adolescents was low at 21.1%. Fewer (17.4%) adolescents reported buying lunches from cafés and shops, compared to adolescents consuming cooked school meals and packed lunches (28.3% and 36.6%, respectively), and they had the lowest DQI-A% score of 14.8%. Adolescents having cooked school meals (reference group) had a higher overall DQI-A% of 21.8%. Diet quality scores of older adolescents having packed lunches and shop/café-bought lunches were 5.5% higher (CI 2.7 to 8.4%; p < 0.01) and 5.0% lower (CI 8.1 to 2.0%; p < 0.01) than cooked school meals respectively, after adjusting for gender, region, energy under-reporting and equivalised household income. For younger adolescents the results were attenuated particularly among packed lunch consumers. UK adolescents generally consume a poor quality diet and adolescents purchasing lunches from outside the school gates have the lowest quality diets. Unlike with older children there is little difference between school meals and packed lunches for younger children. Regulation policies on food outlets around secondary schools as well as improving food choices within school premises are needed.