Impact of including weekend days on dietary intake patterns in Korean adults with metabolic syndrome: a secondary data analysis

Purpose: This study examined the impact of including weekend days in 24-hour dietary recalls on dietary intake patterns and investigated associations between dietary intake—analyzed using nutrient- and food-group–based categories—and cardiovascular risk factors in adults with metabolic syndrome (MetS). Methods: A cross-sectional study analyzed data from 185 adults aged 40-69 years with metabolic syndrome (MetS), who had either a history of cardiovascular disease or an intermediate-to-high 10-year cardiovascular disease risk. Dietary intake was assessed over three days using 24-hour dietary recalls and analyzed with CAN-Pro 4.0. Results: Overall dietary intake did not differ significantly according to the number of weekend days included, except food-group–based protein intake (p = .030). In the no-weekend group, most nutrients and food groups demonstrated relatively consistent correlations between the 3-day average intake and single-day intake (r ≥ .61). In contrast, correlation coefficients varied widely among groups that included weekend days (r = −.08 to .97). Further analyses stratified by specific weekend days (saturdays, sundays, and national holidays) revealed significant differences in nutrient-based protein intake (F = 3.38, p = .011). Both nutrient- and food-group–based dietary intakes were significantly associated with cardiovascular risk factors. Conclusion: The number of weekend days included in dietary assessment may influence estimated dietary intake. The observed variability across specific weekend days suggests that using multiple 24-hour dietary assessments and developing nutritional interventions that explicitly account for weekend schedules would improve the accuracy of dietary pattern assessment and the effectiveness of interventions in individuals with MetS.