A pioneering study in Spain links the environmental impact of our food choices to human health damage

Planetary health and human health are closely interconnected. What harms the environment, whether in the short or long term, also affects human health. With this planetary health approach, a pioneering study in Spain has quantified for the first time the health damage caused by the environmental impacts of our food demand. The results reveal that the consumption of meat, fish and seafood, and dairy products accounts for 55% of the damage to human health. According to the study, changing consumption patterns and reducing food waste could prevent up to 35% of this impact. The research, published in Environmental Research, was led by the Barcelona Institute for Global Health (ISGlobal), a center supported by the “la Caixa” Foundation, with the support of the Daniel and Nina Carasso Foundation.

The research team applied a cutting-edge scientific methodology, Life Cycle Assessment (LCA), to quantify the different environmental impacts of the food system (from production to consumer) and how they affect human health. The data was based on the 2022 food consumption surveys published by Spain’s Ministry of Agriculture, Fisheries and Food. The researchers used statistical models to assess the environmental effects on human health, evaluating various key indicators such as climate change, ozone layer depletion, human toxicity, particulate matter formation, ionizing radiation, and photochemical oxidant formation. The health consequences analyzed included cardiovascular diseases, malnutrition, diarrhea, various types of cancer, and respiratory diseases, among other conditions.

The results indicate that, in 2022 alone, the environmental impact of food demand in Spain was associated with a loss of 447,152 disability-adjusted life years (DALYs). This is a widely used public health metric that combines years lost due to premature death and years lived with illness or disability. Of the total environmental impact from food demand with consequences for health, 95% was attributable to food consumption and the remaining 5% to food waste.

Meat, fish and dairy: the foods that most harm human health through their environmental impact

Among the 16 food groups analyzed, meat, fish and seafood, and dairy products were identified as the main contributors to environmental damage with health consequences, accounting for 55% of the total consumption impact. Additionally, these animal-based foods showed a significantly higher health burden compared to plant-based products.

Among the negative effects of the food system, the contribution to climate change was the main environmental factor associated with health damage, accounting for 77% of the total impact. This was followed by particulate matter formation (16%) and human toxicity (7%). Other impacts such as photochemical oxidant formation, ozone layer depletion, and ionizing radiation contributed to a lesser extent.

Dietary changes that can improve global health

The study evaluated several hypothetical scenarios based on commonly promoted measures to reduce the environmental impact of food, aiming to quantify the potential benefits for human health. In the first scenario, replacing red and processed meat with white meat showed modest benefits. However, the greatest benefit emerged when all meat and dairy were replaced with plant-based foods. This change could reduce the environmental health damage by up to 30%. Additionally, if consumer food waste is eliminated, a further 5% reduction in impact could be achieved, totaling a 35% overall improvement.

The research also aimed to assess the nutritional implications of replacing meat and dairy with plant-based foods. Specifically, the team examined total energy intake as well as key macro- and micronutrients, including protein, saturated fat, fiber, calcium, sodium, iron, zinc, and vitamin B12. With the dietary shift, the nutritional profile aligned more closely with World Health Organization (WHO) recommendations. Intake of protein, calcium, and vitamin B12 would decrease but remain within WHO-recommended ranges. In contrast, fiber and iron intake would increase significantly—an especially relevant finding given the current deficiency of these nutrients in the Spanish diet.

Public health implications

This study not only highlights the strong link between diet, the environment, and health, but also opens new opportunities to improve public health through a more sustainable and responsible diet. “The proposed changes would not only reduce environmental impact but also bring the average diet in Spain closer to WHO nutritional recommendations, thus moving toward a more comprehensively healthy diet,” says Ujué Fresán, ISGlobal researcher and lead author of the study.

Moreover, the research provides a solid scientific foundation to guide the development of future food policies. “Our findings can serve as a starting point for designing and implementing policies that promote the transition to healthier eating habits in Spain, considering both the direct and indirect benefits for human health,” adds Fresán.

Reference

Fresán, U., Núñez, M., Valls, I., Rosenbaum, RK. Quantifying the Environmental Human Health Burden of Food Demand in Spain: A Life Cycle Assessment Study. Environmental Research, 2025. Doi: 10.1016/j.envres.2025.122147