Meal timing associations on dietary quality and glucose response

Abstract Background When and how often we eat is increasingly recognized as relevant to metabolic health alongside what and how much we eat, but real-world evidence linking these temporal eating patterns to diet quality and metabolic outcomes remains limited. We assessed how meal timing and eating occasion (EO) frequency relate to nutrient intakes, body mass index (BMI), and postprandial glucose in a free-living digital cohort. Methods We analyzed dietary data from 962 Swiss adults enrolled in the Food & You digital cohort (2018–2023), who logged meals in real time, with continuous glucose monitoring providing postprandial traces. Associations were modeled at the participant and meal level using partial correlations and regression modeling, with mediation analysis testing whether EO frequency explained meal-timing-BMI associations. Results Here we show that associations between EO frequency and dietary quality vary by age and BMI: among people living with obesity, the relationship is negative in younger adults (<35; R = −0.32) but positive in those over 50 (R = 0.52). Across the cohort, EO frequency is positively associated with diet diversity (r ≈ 0.2) and negatively with meal skipping (e.g., breakfast r = −0.35). A higher proportion of breakfast energy is associated with lower BMI (β = −6.23, 95% CI: −8.98 to−3.49), while a higher lunch energy share is associated with higher BMI (β = 4.84, 95% CI: 1.83 to 7.86), and EO frequency explains less than 6% of these associations. Weekend patterns show higher discretionary food intake (+6 to + 16 g across meals) and reduced lunch intake of fruits and grains. Postprandial glycemic response increases with carbohydrate load (β = 0.19), is attenuated by protein, fat, and alcohol, and is further suppressed by recent glucose excursions within 1 h (β = −0.09). Conclusions Meal timing, eating frequency, and weekend behaviors are associated with dietary quality, BMI, and glycemic control. These associations vary by age, time of day, and day of week, and are relevant for age- and timing-aware dietary guidance.