Assessing Gender and Age Differences in the Adoption of Sustainable Diets: Insights from an Intervention of the Mediterranean Diet

Introduction: Sustainable nutrition is integral to environmental health and conservation. Gender and age differences influence dietary patterns, but their impact on the adoption of sustainable diets remains unclear. This study investigates the effects of a Mediterranean diet intervention on diet sustainability, focusing on gender and age differences. Methods: A cross-sectional study was conducted on 1666 participants (58.2% women) aged 18–75 years. Dietary preferences were assessed through food diaries and sustainability indices before and after the intervention. Participants followed a low-calorie Mediterranean diet for two months, with food diaries tracking their weekly consumption. Changes in sustainable and non-sustainable food consumption were analysed using paired t -tests and stratified by gender and age groups. Results: Men consumed significantly more meat and processed meat ( p < 0.001), while women preferred low-fat yoghurt and whole grains ( p < 0.01). Despite an increase in legume consumption (3.2%, p < 0.001), the overall sustainability index decreased due to a compensatory rise in meat consumption among men ( p < 0.001), particularly in younger (<30) and older (>50) participants. Gender-related differences were observed, with female participants reporting a higher intake of foods classified as sustainable. However, significant cultural and palatability barriers limited the uptake of some sustainable foods such as tofu. Discussion: The intervention highlighted the challenges in promoting sustainable eating habits. Gender-targeted and age-specific strategies are critical to overcome barriers and support dietary improvements. Future interventions should incorporate cultural preferences and provide long-term support to achieve significant changes in behaviour. Conclusions: The Mediterranean diet intervention, conducted within an Italian cohort, highlighted both opportunities and challenges in promoting sustainable dietary transitions. Tailor-made approaches are essential to meet the different needs of various demographic groups. However, the effectiveness of nutrition programmes focusing on sustainability may depend on local food availability, cultural acceptance and dietary traditions.