Background <p>The growing emphasis on sustainability in recent years has been largely driven by the pressing challenges of climate change. In this context, healthy diet literacy represents a critical approach to promoting the sustainability of the food system, which has far-reaching implications for both public and environmental health.</p> Methods <p>This cross-sectional study included 495 university students. The questionnaire form consists of the nutritional habits and anthropometric measurements of university students, “e-Healthy Diet Literacy Questionnaire (e-HDLQ)”, and “Sustainable and Healthy Eating (SHE) Behaviors Scale”.</p> Results <p>The mean age of the participants was 19.26 ± 2.19 years, with a mean BMI of 22.40 ± 4.04&#xa0;kg/m². A one-unit increase in e-HDLQ was significantly associated with a 0.709 unit (95%CI: 0.289; 1.130) increase in SHE behaviors and demonstrated significant explanatory power (R² = 0.022, <i>p</i> &lt; 0.001). A one-unit increase in e-HDLQ was significantly associated with sub-dimensions of SHE behaviors: quality labels (β = 0.154, R² = 0.013, <i>p</i> &lt; 0.001), animal welfare (β = 0.146, R² = 0.028, <i>p</i> &lt; 0.001), meat reduction (β = 0.093, R² = 0.026, <i>p</i> &lt; 0.001), healthy and balanced diet (β = 0.119, R² = 0.011, <i>p</i> &lt; 0.05), local food (β = 0.091, R² = 0.020, <i>p</i> &lt; 0.001) and low-fat (β = 0.063, R² = 0.008, <i>p</i> &lt; 0.05).</p> Conclusions <p>The study’s outcomes underscore the need to design educational initiatives that connect nutrition literacy with sustainable and healthy nutritional behaviors. To enhance their effectiveness, such initiatives should be integrated into interdisciplinary academic frameworks, targeting individual health and environmental sustainability improvements.</p> Trial registration <p>This is cross-sectional research conducted on human participants but does not require intervention.</p>