**Background:** The food system accounts for 28–34% of global greenhouse gas emissions, and dietary patterns high in animal products contribute disproportionately to environmental degradation. The EAT-Lancet Commission recommends a minimum 50% reduction in red meat and sugar consumption and a more than 100% increase in fruits, vegetables, and pulses. Despite the critical role healthcare professionals play in promoting health, limited research has examined their knowledge, attitudes, and habits regarding sustainable diets. This study aimed to evaluate these factors among health science students and professionals in Spain and compare them to the general population.
**Methods:** A cross-sectional study was conducted between December 2021 and April 2022 using online questionnaires. A convenience sample of 415 participants was recruited: 327 students (78.8%) from the University of the Basque Country (UPV/EHU) and the Open University of Catalonia (UOC), and 88 health professionals (21.2%) including UOC faculty and members of the Barcelona Official College of Pharmacists. The survey adapted a validated questionnaire from a prior Spanish population study, adding three questions on food waste. Knowledge was assessed via yes/no/unknown responses to sustainability concepts, Likert-scale ratings of sustainable food priorities, and perceived environmental impact of food groups. Attitudes were measured across cognitive, affective, and behavioral dimensions. Food consumption frequency was assessed using a validated food frequency questionnaire. Knowledge and attitude indices were constructed and correlated with dietary habits using Spearman correlations. Statistical significance was set at p<0.05.
**Key Results:** Among 415 participants (361 women, 52 men, 2 nonbinary; mean age 27.73 years), knowledge of sustainability concepts was high: 92.00% knew greenhouse gas emissions, 89.80% biodiversity, 60.00% carbon footprint, and 56.10% environmental footprint. Only 12.30% were familiar with the term "water footprint." Regarding sustainable diet priorities, 70.36% rated "healthy for humans" as very important, 62.65% fresh products, 62.41% local products, 61.69% biodiversity, and 60.24% low environmental impact. Only 14.70% considered "few ingredients" very important. For environmental impact perceptions, 53.01% correctly identified plant-based foods as having low impact, while 75.42% recognized red meat, 82.89% processed meat, and 84.58% ultraprocessed foods as high impact. Dairy was rated as moderate impact by 44.82% and high impact by 40.00%. Attitudes were generally positive: 70.60% considered sustainable food production important or very important, 59.03% were willing or very willing to pay more for sustainable food, and 64.34% stated buying sustainable food was important or very important. Food waste was low, with 84.34% never or rarely leaving food on their plate. Dietary habits showed 67.47% consuming fruits 1–2+ times daily, 62.89% vegetables, and 48.19% dairy daily. Red meat was consumed 1–2 times or fewer per week by 82.89%, and 32.29% never ate processed meat. Spearman correlations revealed significant positive associations between knowledge/attitude scores and vegetable consumption (ρ=0.303, p<0.001) and fruit consumption (ρ=0.161, p<0.001). Significant negative correlations were found with red meat (ρ=−0.230, p<0.001) and processed meat (ρ=−0.158, p=0.001). Dairy showed a non-significant negative correlation (ρ=−0.062, p=0.205).
**Clinical Implications:** Health science students and professionals demonstrate greater knowledge of food sustainability and healthier dietary patterns compared to the general Spanish population, where over 50% were unaware of meat's environmental impact. The significant correlation between knowledge and sustainable dietary habits supports the integration of food sustainability into health sciences curricula. Healthcare professionals are well-positioned to promote both healthy and sustainable diets, but may need targeted education on less familiar concepts like water footprint. Policy measures including fiscal strategies to reduce prices of sustainable foods and increase costs of high-impact foods may be necessary to support population-level dietary change, as price remains a major barrier for 65% of the general population.