School Schedule Effect on Students’ Eating Habits and Body Composition

Abstract Background Epidemiological studies show that chrono disruption is a risk factor for overweight and obesity. Mealtimes and the type of food consumed are known to affect peripheral clocks and circadian rhythms. In this research we map how students differ in their eating habits and body composition according to age, gender and school schedule. Methods The sample includes 97 students (6 to 18 years of age), enrolled in primary schools or secondary (high) schools in the province of Valencia (Spain). Data was gathered between 2023 and 2025. In this paper we present a cross-sectional analysis of the data. Assessment of food intake and timing is done through a feeding diary filled on a Monday, a Thursday and a Sunday to understand eating patterns and to assess macro and micronutrients at the individual level. Anthropometric evaluation is used to record health parameters such as weight and height, body composition, skin folds and waist circumference. Results Our preliminary analysis display: 1) chrono nutrition data shows that students tend to advance breakfast on school days in comparison with weekend days (by almost three hours in the case of highschool), and those attending compact schedule delay lunch time in almost two hours; 2) anthropometry shows significant differences in skeletal muscle and weight showing greater values for those attending the split schedule (19,1 and 41,1 respectively) than the compact schedule (18,8 and 40,5 respectively). Conclusions School schedules force students to feed in hours that are not fitted to their needs. For the case of Spain desynchronization with solar time makes schools entry to be too early. Students attending split school schedule present higher BMI due to higher skeletal muscle. Key messages • Desynchronized mealtimes relates to school-age children having higher odds of being overweight and obese. • We recommend delaying school entry times and respect lunch break.