Well-balanced and predominantly plant-based diets can lead to improved nutrient levels, reduce premature deaths from chronic diseases by more than 20%, and lower greenhouse gas emissions, fertiliser application, and cropland and freshwater use, according to new research.
The study, published in The Lancet Planetary Health, is reportedly the first to comprehensively assess the relationship between the health and nutritional impacts of different dietary-change strategies and their environmental impacts across all major world regions.
“We investigated the aspects of our diets that we should change to improve health and nutrition around the world whilst at the same time reducing environmental impacts whenever possible,” said Dr Marco Springmann, from the University of Oxford, who led the study.
The team considered three different dietary-change strategies, including replacing animal products with plant-based ones, improving weight levels by addressing both over- and under-consumption of calories, and adoption of well-balanced and predominantly plant-based diets that reflect the current scientific evidence on healthy eating, including flexitarian (semi-vegetarian), pescatarian, vegetarian, and vegan diets. The researchers then assessed the impacts of these strategies on nutritional deficiencies, chronic-disease mortality and environmental impacts, including greenhouse gas emissions, freshwater use, cropland use, and nitrogen and phosphorus application from fertilisers for more than 150 countries.
They found that replacing animal products with plant-based ones was particularly effective in high-income countries for improving nutrient levels, lowering chronic-disease mortality, and reducing some environmental impacts, in particular greenhouse gas emissions. However, it also led to increased freshwater use, and had little effectiveness in countries with low or moderate consumption of animal products.
Adoption of healthy, energy-balanced and predominantly plant-based dietary patterns led to an adequate supply of most nutrients in most regions, and large reductions in chronic disease mortality that ranged from 19% for flexitarian diets to 22% for vegan diets. The energy-balanced and predominantly plant-based diets also led to reduced environmental impacts globally and in most regions.
Springmann called for national dietary guidelines to be updated to reflect the latest evidence on healthy eating. “Many national dietary guidelines do not reflect the latest scientific evidence on healthy eating and include no or very lax limits for animal products, particularly meat and dairy,” he said.
Research published in 2016 showed that only four countries included sustainability in their food based dietary guidelines. Brazil, Germany, Sweden and Qatar all highlight that a largely plant-based diet has advantages for health and for the environment.