The environmental gains of dietary change are often assessed in relation to average national diets, overlooking differences in individual consumption habits and people's willingness to change. This study combines microdata on food intake and consumer behaviour to elicit the likely environmental gains of dietary shifts. We focus on the Netherlands owing to the country's ambition to halve its dietary footprint by 2050. Linking food recall survey data from a cross-section of the population (n = 4313), life cycle inventory analysis for 220 food products, and behavioural survey data (n = 1233), we estimate the dietary footprints of consumer groups across water, land, biodiversity and greenhouse gas (GHG). We find that meat and dairy significantly contribute to the dietary GHG footprint (59%), land footprint (54%), and biodiversity footprint (59%) of all consumer groups and that male consumers impose a 30%-32% greater burden than women across these impact areas. Our scenario analysis reveals that simply replacing cow milk with soy milk could reduce the GHG, land and biodiversity footprints by approximate to 8% if widely adopted by the Dutch adult population. These footprints could be further reduced to approximate to 20% with full adoption of the EAT-Lancet diet but with a significantly increased blue water footprint. However, when incorporating gender- and age-specific willingness to reduce meat and dairy consumption, the environmental gains resulting from partial adoption of the No-Milk diet and EAT diet diminish to a mere approximate to 0.8% and approximate to 4.5%, respectively. Consequently, consumer motivation alone is insufficient to realise the significant environmental gains often promised by dietary change. Yet, substituting high-impact food products offers a near-term opportunity to accelerate a rapid sustainable dietary transition. Future studies on sustainable dietary transition must incorporate consumer behaviour to fully comprehend the lock-in of food consumption patterns and targeted policy action required to secure a sustainable food future.
