The Carbon Footprint of Diets with Different Exclusions of Animal-Derived Products: Exploratory Polish Study

Abstract

Background/Objectives: Analyzing the carbon footprint of diets in various populations is important as it can help identify more sustainable food choices that reduce the overall impact of human activities on ongoing warming of the global climate. This pilot exploratory study analyzed the carbon footprint (measured in kg of CO₂ equivalent, eq.) using food diaries collected from Polish individuals with varying levels of animal-derived product exclusion in their diets. Methods: The study employed a food diary method, where participants from four dietary groups (vegan, vegetarian, fish-eater, and meat-eater) recorded all meals and beverages consumed over a 7-day period, including portion sizes and packaging details. These diaries were then analyzed to assess dietary adherence and calculate carbon footprints, utilizing standardized CO₂ equivalent emission data from publicly available databases. Results: The analysis revealed a decreasing trend in the carbon footprint corresponding to the degree of elimination of animal-derived products from the diet (R² = 0.96, p = 0.0217). The mean daily footprint in the vegan group was 1.38 kg CO₂ eq., which was significantly lower than in the vegetarian (2.45), fish-eater (2.72), and meat-eater groups (3.62). For each 1000 kcal, the meat-eater diet generated 39.7, 58.3, and 93.9% more CO₂ eq. than in the case of fish-eaters, vegetarians, and vegans, respectively. Over a week, a group of 10 vegans had a total carbon footprint lower than vegetarians, fish-eaters, and meat-eaters by 42.9, 52.2, and 61.8%, respectively. Hard and mozzarella cheese had the highest contribution to the carbon footprint in vegetarians, fish, and seafood in fish-eaters, and poultry, pork, and beef had the highest contribution in meat-eaters. Conclusions: Dietary carbon footprints vary considerably by dietary pattern, with lower consumption of animal-derived products associated with lower emissions. Additionally, identifying specific high-impact food items within each diet may inform strategies for reducing environmental impact across various eating patterns.

Keywords: animal products; climate change; environment; plant-based diets; sustainability.

Figure 1

The carbon footprint of a particular diet group (n = 10) presented as (A) total daily CO₂ eq. and (B) daily CO₂ eq. standardized over energy intake. Points represent mean, whiskers represent a 95% confidence interval, green and red lines represent minimal and maximum value, respectively, and the dotted violet line represents the best-fit line between the level of elimination of animal-derived products and carbon footprint. Different letters denote statistically significant differences (p < 0.05) between groups in post-hoc tests following ANOVA; the same letters indicate no differences between compared groups. (C) Total weekly carbon footprint of each group consisting of 10 individuals with mean per capita values given above the bars.