P3.014: How Health Behaviors Shift Across High School Grades 9-12

Background: Establishing healthy nutritional and physical activity habits in childhood is essential for preventing future obesity and other lifestyle-related diseases. This study aims to examine how lifestyle behaviors evolve from 9th to 12th grade by analyzing differences in nutrition, extracurricular activity, and caffeine use between underclassmen and upperclassmen. These insights may help guide the development of supportive, age-appropriate health interventions for high school students.

Methods: We conducted a cross-sectional voluntary survey of high school students in Texas. The survey collected information regarding demographics, physical activity, nutrition, sleep habits, mood, and GI symptoms. Survey responses (n=206) were analyzed by grade level. Key measures included sports team participation, family meals, fast food consumption, breakfast habits, sleep, and caffeine use. We used ANOVA and chi-square tests to detect grade-associated trends. Significant pairwise differences were examined with post-hoc comparisons

Results: Physical activity and extracurriculars: 9th-graders reported the highest sports team involvement (mean 1.74 teams in the past year) which declined by 11th–12th grade (~1.18 teams, p=0.03). Despite expectations, self-reported sleep duration did not significantly differ by grade with an average of 7 hours per day. Nutrition: Regular family meal frequency was similar across grades, but older students were more likely to skip school-day meals. By junior year, 42% skipped breakfast (vs ~33% of freshmen) however, this difference was not statistically significant (p = 0.32). Lunch skipping remained low (≈5% overall). Fast-food consumption was common, with roughly 25% of students in each grade reporting three or more fast-food meals per week, showing no significant trend by grade. Caffeine use: A sharp increase was seen in daily caffeine intake among seniors – 36% of 12th-graders consumed caffeine daily (coffee/energy drinks), compared to 15.2% in 9th grade (p < 0.02). Seniors were also the most likely to consume caffeine multiple times a day (15%) versus 3.5% in 10th graders (p < 0.05).

Conclusion: Several health behaviors shift over the course of high school. Younger students are more likely to participate in organized sports, while older students tend to adopt more independent routines—some of which may include unhealthy habits, such as skipping breakfast or relying on caffeine to manage academic and scheduling pressures. These findings highlight the need for grade-specific interventions that encourage sustained involvement in sports and extracurricular activities beyond 9th grade, as well as the promotion of healthy nutrition and sleep habits as students enter their junior and senior years.