Convenience-Oriented Dietary Behavioral Patterns Across BMI Classes in University Students: Associations with Overweight and Obesity Risk During the Transition to University Life

Background/Objectives: Convenience-oriented dietary behaviors acquired during the transition to university life may be associated with overweight and obesity status in young adults. This study aimed to characterize the dietary behaviors of Romanian university students and to evaluate their associations with overweight and obesity. Methods: This cross-sectional study included 921 university students aged 18–24 years (60.6% female; 67.8% urban residents). Self-reported dietary variables included fast-food consumption, sweets intake, fruit and vegetable intake, water intake, and replacement of meals with desserts. BMI categories were classified according to WHO criteria. Associations were evaluated using chi-square tests, Cramer’s V, and multivariable logistic regression adjusted for sex, age group, and residence environment. A five-item Dietary Risk Score (DRS; range 0–5) was constructed as an exploratory composite indicator of cumulative dietary behavioral burden. Cluster analysis was additionally performed to identify dietary behavioral phenotypes. Results: A total of 24.1% of participants were classified as overweight/obese, including 19.4% overweight and 4.7% obesity. Frequent replacement of meals with desserts (aOR 7.20; 95% CI 4.26–12.17) and fast-food consumption ≥3 times/week (aOR 1.98; 95% CI 1.26–3.10) were independently associated with overweight/obesity after adjustment for demographic variables. Male sex, older age, and urban residence were also independently associated with overweight/obesity. Distinct dietary behavioral phenotypes were identified, including a convenience-oriented cluster characterized by higher fast-food and sweets intake and the highest prevalence of overweight/obesity. The DRS demonstrated a dose–response relationship with overweight/obesity prevalence, increasing from 19.8% at DRS = 0 to 50.0% at DRS = 4, with an adjusted OR of 1.43 per one-point increase (95% CI 1.23–1.66; p < 0.001). Conclusions: Frequent meal replacement with desserts, higher fast-food consumption, and greater cumulative dietary behavioral burden were associated with overweight and obesity status among Romanian university students. The findings support the relevance of evaluating cumulative dietary behavioral patterns in young adults; however, the cross-sectional design precludes conclusions regarding causality or temporal directionality.