EnComCol Study on the diet of children and young people at home and in schools: design and methodology.

EnComCol is an observational, crosssectional, multicentre study assessing diet in Spanish children and adolescents (6-17 years) by comparing intake at home with that in the school canteen. It is framed by the continuing burden of childhood overweight/obesity and Royal Decree 315/2025, which harmonises criteria for school menus and portions. The main aim is to identify differences in foods, beverages and nutrient intake according to canteen use, school ownership (public, charter, or private) and residence across six mainland regions, considering six daily mealtimes eating occasions. The sample comprises 1,000 urban participants, balanced by age (50 % 6-11; 50 % 12-17) and sex, with quotas for school type (75 % public, 20 % charter, 5 % private) and geographic distribution using Nielsen areas. For ages 6-11, quotas ensure a 50/50 split between canteen users and nonusers. Methods include a structured 24 hours recall dietary record plus sociodemographic, anthropometric and lifestyle variables. Data collection has three phases: recruitment and a technology-assisted interview; a food diary with telephone interview; and researcher telephone validation, with digital coding and nutrient conversion using updated food-composition tables. Analyses will use descriptive and inferential statistics, mean/proportion comparisons, multivariable models and stratification by age, sex, school type, canteen use and region (p < 0.05). Findings will enable direct comparison with prior research and quantification of critical nutrients (saturated fat, sugars and salt) across contexts.