Environmental impact of omnivorous, ovo-lacto-vegetarian, and vegan diet

TLDR

Food and beverage consumption significantly impacts the environment, yet comprehensive dietary data are scarce. The study assessed the environmental impact of omnivorous, ovo‑lacto‑vegetarian, and vegan diets among 153 Italian adults. Participants recorded 7‑day dietary intake, from which carbon, water, and ecological footprints were calculated and nutritional quality was evaluated using the Italian Mediterranean Index. Omnivorous diets produced higher carbon, water, and ecological footprints than plant‑based diets, which showed similar, lower impacts but high individual variability, highlighting the importance of personal dietary choices and marking the first study to evaluate these regimens with recorded intakes.

Abstract

Food and beverage consumption has a great impact on the environment, although there is a lack of information concerning the whole diet. The environmental impact of 153 Italian adults (51 omnivores, 51 ovo-lacto-vegetarians, 51 vegans) and the inter-individual variability within dietary groups were assessed in a real-life context. Food intake was monitored with a 7-d dietary record to calculate nutritional values and environmental impacts (carbon, water, and ecological footprints). The Italian Mediterranean Index was used to evaluate the nutritional quality of each diet. The omnivorous choice generated worse carbon, water and ecological footprints than other diets. No differences were found for the environmental impacts of ovo-lacto-vegetarians and vegans, which also had diets more adherent to the Mediterranean pattern. A high inter-individual variability was observed through principal component analysis, showing that some vegetarians and vegans have higher environmental impacts than those of some omnivores. Thus, regardless of the environmental benefits of plant-based diets, there is a need for thinking in terms of individual dietary habits. To our knowledge, this is the first time environmental impacts of three dietary regimens are evaluated using individual recorded dietary intakes rather than hypothetical diet or diets averaged over a population.