Sex-related differences in nutrition and lifestyle in childhood and adolescence: a clinic-based cross-sectional study from Central Italy

Background Sex and gender differences influence nutritional needs, behaviours, and health trajectories from early life, yet paediatric evidence remains limited. This study investigated sex- and age-specific differences in nutritional habits, lifestyle behaviours, and nutritional status in the paediatric population of Gaeta (Central Italy). Methods We conducted a cross-sectional prevalence survey on 610 children and adolescents aged 1–16 years (305 boys, 305 girls) recruited at a territorial paediatric outpatient clinic between January 2022 and March 2023; recruitment was consecutive and clinic-based. Data collected through structured questionnaires included BMI category, infant feeding, breakfast habits, legume and vegetable intake, snack consumption, physical activity, and television viewing time, stratified by sex and age group (1–5, 6–11, 12–16 years). Associations were tested using chi-square and Mann–Whitney tests ( p < 0.05). Results The majority of participants were normal weight (79.2%), with no significant sex difference in BMI distribution ( p = 0.221); however, obesity was more prevalent among adolescent boys than girls (9.7% vs. 1.7%). Exclusive breastfeeding was reported in 42.1% of the sample and declined across age cohorts (50.7% in 1–5 years vs. 30.3% in 12–16 years; p = 0.010). Complete breakfast was consumed by 65.9% overall and was significantly more frequent in boys than girls (70.8% vs. 61.0%; p = 0.036); breakfast skipping increased with age from 0% in preschoolers to 9.0% in adolescents ( p = 0.012), with adolescent girls showing the lowest rate. Legume consumption reached ≥ 3 times/week in only 25.1% of participants, while frequent vegetable intake was reported by 46.6%, with a higher though non-significant prevalence in girls (50.2% vs. 43.0%; p = 0.088). Low or absent physical activity was found in 36.6% overall, significantly more common in girls (41.0% vs. 32.1%; p = 0.029) and following a non-linear pattern across age groups ( p < 0.001). Television viewing time exceeding two hours per day was reported by 21.5%, with adolescent boys showing the highest prevalence (29.0%) and adolescent girls the lowest (13.3%; p = 0.058). Conclusions Sex- and age-specific differences in nutrition and lifestyle emerge early and intensify during adolescence. These findings highlight the need for sex- and age-sensitive preventive strategies targeting particularly breakfast regularity and physical activity, and reduction of excessive television viewing time.