LB009 - VARIATION IN DIETARY INTAKE ACROSS THE DAYS OF THE WEEK

LB009

VARIATION IN DIETARY INTAKE ACROSS THE DAYS OF THE WEEK

T. Zetterlund¹, H. M. Lindqvist^1,*, A. Winkvist¹

¹Department of Internal Medicine and Clinical Nutrition, University of Gothenburg, Gothenburg, Sweden

Rationale: Dietary habits may vary over time, across the days of the week, between sexes, and between age groups. Previous studies have reported differences between weekdays and weekends, but there is no consensus on how days should be categorized in dietary assessment. Since dietary intake is often assessed using 3–4-day food diaries, understanding day-to-day variation is important for improving dietary assessment in clinical practice and research.

Methods: Seven-day food diaries were collected in 2025–2026 from healthy adults aged 18–65 years in Gothenburg, Sweden, as part of the BARITONE study. Nutrient intake was estimated using Dietist Net based on The Swedish Food Composition Database. Monday through Thursday were classified as weekdays. Friedman’s ANOVA with pairwise comparisons and Bonferroni correction was used to identify differences in intake across types of days. Analyses were conducted for the total sample and stratified by sex and age group.

Results: Eighty-eight participants were included. Significant differences in dietary intake were observed between weekdays, Fridays, Saturdays, and Sundays (p<0.05). In the total sample, energy intake, saturated fat, alcohol, fiber (g/d), and energy percentages (E%) from protein and alcohol differed across the week. Sex- and age-stratified analyses revealed different patterns of variation across the week. Younger adults differed in E% from free sugars, whereas older adults showed differences in energy intake, alcohol (g/d), and E% from protein and alcohol.

Conclusion: Fridays differed from Monday–Thursday more than from Saturdays, indicating that Fridays should not be considered to represent weekday dietary intake. Sundays shared characteristics with both weekdays and Saturdays. Our findings suggest that 3–4-day food diaries should include 2–3 weekdays (Monday–Thursday) and either a Friday or a Saturday, to better capture habitual dietary intake.

Disclosure of Interest: None declared