Strategies to improve packed lunches should move beyond parental nutrition knowledge and importance of lunch packing to address parental barriers and facilitators.

The BSD may have unintended negative consequences on the type and amount of foods packed in school lunches. Support for families should focus on encouraging more vegetables and fruit and fewer SSBs and snacks in packed lunches.

This study compared the caloric and nutrient values of packed lunch contents and consumption in the Balanced School Day (BSD) (two 20 min eating periods) versus the Traditional Schedule (TS) (one 20 min lunch). Foods consumed during school were assessed by direct food observation in 321 grade 3 and 4 students, aged 7–10 years, at 9 BSD and 10 TS elementary schools in Ontario. Packed lunch contents in the BSD were significantly higher than the TS in energy (3128.14 ± 1100.36 vs. 2658.98 ± 951.34 kJ, p < 0.001, respectively). Similarly, carbohydrates, total sugar, protein, fat, saturated fatty acids (SFA), calcium, iron, and sodium were significantly higher in the BSD versus TS packed lunches. Correspondingly, students in the BSD consumed significantly more energy, carbohydrates, total sugar, and SFA compared to the TS. Overall, lunches brought by students in the BSD schedule provided more energy across all macronutrients, with only a few micronutrients showing increased amounts, suggesting two 20 min eating opportunities could contribute to excess caloric intake during school, potentially contributing to the prevalence of childhood overweight and obesity in Canada. Furthermore, packed lunches in both schedules had excess amounts of nutrients of concern and much work is needed to ensure that children in Canada receive nutritious lunches at school.