An analysis of diet sustainability among different dietary patterns in the Portuguese adult and elderly population

Purpose: Dietary patterns influence human and environmental health. Shifts toward convenience and ready-to-eat ultra-processed foods have contributed to the rising prevalence of malnutrition, chronic disease, and ecological harm. This study examined the associations between dietary patterns and diet sustainability among Portuguese adults. Methods: Data from 2287 individuals aged 18–84 years were obtained from the last National Food, Nutrition, and Physical Activity Survey (2015–2016). Three dietary patterns were identified based on food composition and processing: Traditional, Diet Concerns, and Unhealthy; while four dietary patterns were categorized according to food preparation location: At home by themselves, At home by relatives or friends, By food retail, and By restaurants/canteens. Diet sustainability was assessed using the Diet Sustainability Score (DSS), encompassing health-related nutritional, environmental, economic, and sociocultural dimensions. Linear regression models adjusted for sex, age, education and energy intake were used to estimate associations between dietary patterns and DSS. Results: Traditional (β = 1.27, p < 0.001) and Diet Concerns (β = 1.60, p < 0.001) patterns were significantly associated with higher DSS compared to the Unhealthy pattern. In terms of food preparation location, only the By restaurants/canteens pattern was significantly associated with lower DSS (β = − 0.76; p < 0.001) compared to the At home by themselves pattern. Younger, urban, and more educated individuals were more likely to follow the Unhealthy or the By restaurants/canteens patterns. Conclusion: These findings underscore the need to consider what people eat, how and where food is prepared. Promoting traditional, minimally processed, and home-prepared meals may be essential to advancing sustainable diets, particularly among younger and urban populations.