Background <p>Young adulthood is a period in which long-term lifestyle patterns are established. Barriers such as time constraints, low motivation, and environmental limitations may reduce participation in physical activity and hinder healthy nutritional behaviours. This study examined the relationships among nutritional attitudes, barriers to physical activity, general motivation, and body composition in university students.</p> Method <p>A cross-sectional design was used with 600 students (<i>M</i> = 21.08 ± 1.85_years; 50% women). Nutritional attitudes, physical activity barriers, and general motivation were assessed using validated scales, and body composition was measured using bioelectrical impedance analysis. Analyses included t-tests, correlations, and multiple regression. Regression models were structured to examine how nutritional attitudes and general motivation relate to perceived barriers, aligning the analytical approach with the theoretical framework. Regression assumptions and sampling procedures were checked prior to analysis.</p> Results <p>Students showed moderately positive nutritional attitudes (<i>M</i> = 40.53) and perceived personal factors as the most prominent barriers (<i>M</i> = 30.19). Men scored higher in nutritional attitudes, whereas women reported higher barrier perceptions and higher general motivation levels. Nutritional attitudes were negatively associated with barriers (<i>r</i> = –.332), and general motivation showed a weaker but significant negative association (<i>r</i> = –.189). Nutritional attitudes predicted 11% of the variance in barriers (R² = 0.110), increasing to 12.5% when general motivation was included. Positive nutritional attitudes were associated with higher muscle mass (β = 0.270) and lower fat percentage (β = –0.156), while barrier perceptions showed the opposite pattern. The negative association between barriers and all motivation subscales (including amotivation) indicates that higher barriers correspond to lower overall motivational engagement rather than increased amotivation.</p> Conclusion <p>Integrating behavioural scales with body composition measures shows that nutritional attitudes, general motivation, and perceived barriers jointly shape students’ healthy lifestyle profiles. These findings can inform gender-sensitive, university-based health promotion programs designed to reduce barriers and strengthen students’ overall motivational regulation.</p>