Is chronotype associated with ultra-processed food consumption in adolescents? Results from the EHDLA study

The consumption of ultra-processed foods (UPFs) among adolescents has risen sharply, contributing to poor dietary quality and adverse health outcomes. Chronotype, an individual's preference for morning or evening activity, has been linked to lifestyle behaviors, but its association with UPF intake in adolescents remains unclear. This study aimed to examine whether chronotype is associated with UPF consumption in a representative sample of Spanish adolescents. A cross-sectional analysis was conducted using data from 820 adolescents aged 12-17 years participating in the Eating Healthy and Daily Life Activities (EHDLA) study in Murcia, Spain. Chronotype was assessed with the Morningness/Eveningness Scale for Children (MESC). UPF consumption was measured via a validated food frequency questionnaire and classified according to the NOVA system. Associations between chronotype categories (eveningness, intermediate, morningness) and UPF intake were analyzed using robust generalized linear models, adjusting for sociodemographic and lifestyle covariates. Adolescents with an evening chronotype had the highest predicted UPF consumption (34.7 servings/week; 95% confidence interval [CI] 33.0 to 36.3), followed by those with an intermediate chronotype (33.4; 95% CI 32.6 to 34.1), and those with a morning type (31.9; 95% CI 31.0 to 32.8). Pairwise comparisons showed that morning types consumed less UPFs than evening types (difference = -2.8; 95% CI -4.7 to -0.8; p = 0.005). Furthermore, a significant distinction was observed between the intermediate and morning chronotype groups (-1.4; 95% CI -2.6 to -0.3; p = 0.018).

Adolescents with an evening chronotype show higher UPF consumption than those with morning or intermediate chronotypes, even after adjusting for key sociodemographic, anthropometric, and lifestyle factors. These findings suggest that chronotype status may influence unhealthy eating behaviors, highlighting the need for chronotype-tailored interventions to reduce UPF intake in this vulnerable population.

• The consumption of ultra-processed foods (UPFs) in children and adolescents is linked to higher risks of obesity, metabolic disorders, and chronic diseases. UPFs are rich in calories, sugars, and unhealthy fats, undermining diet quality. Studies report a dose-response relationship between UPF intake and overweight/obesity risk, supporting urgent preventive measures.

• Emerging research connects chronotype (a person's biological timing preference for activities) with dietary habits. Evening chronotypes tend to consume more UPFs, engage in late-night eating, and have a poorer diet quality. This study reveals that Spanish adolescents with an evening chronotype consume significantly more UPFs than those with morning or intermediate chronotypes, highlighting potential targets for public health strategies.