Gender- and Age-Related Differences in Sustainable Dietary Transitions during a Mediterranean Diet Intervention

This study explored the influence of gender and age on sustainable dietary transitions during a Mediterranean diet intervention in adults attending a nutritional outpatient clinic. Sustainable eating patterns are increasingly recognized as important strategies for improving both human and environmental health; however, demographic factors may influence adherence to these dietary models.

1666 participants (58.2% women) aged 18–75 years followed a calorie-restricted Mediterranean dietary intervention, and food intake was evaluated before and after treatment using dietary questionnaires and a sustainability index. Changes in dietary habits were analysed according to sex and age groups (<30, 30–50, and >50 years).

At baseline, men reported higher consumption of meat and processed meat products (p < 0.001), whereas women consumed more whole grains and low-fat dairy products (p < 0.01). Following the intervention, legume consumption increased significantly (+3.2%, p < 0.001), although the overall sustainability index decreased in the total sample. Significant reductions in sustainability scores were observed in participants aged <30 years (0.27 vs. 0.19; p = 0.0019) and >50 years (0.27 vs. 0.19; p = 0.0005), while smaller changes were observed in the 30–50-year group (0.30 vs. 0.25; p = 0.0123). Men showed a greater tendency toward increased meat consumption after the intervention, whereas women maintained more sustainable dietary choices.

These findings suggest that short-term Mediterranean dietary interventions do not automatically improve sustainability-related behaviours, particularly in specific demographic groups. Gender- and age-specific nutritional strategies may therefore be necessary to facilitate long-term adherence to sustainable dietary patterns and reduce resistance to plant-based food choices.