Balanced
plant-based diets improve our health and the health of the planet
Oxford University
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, fertilizer application, and cropland and freshwater
use, globally and in most regions, a new study reports.
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, fertilizer application, and cropland and freshwater
use, globally and in most regions, a new study reports.
The
study, published in The Lancet Planetary Health, is 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.
'The food people eat impacts their health and the health of the environment. Unhealthy diets, overconsumption, and hunger are leading to nutritional deficiencies and diet-related chronic diseases around the world. The food system is also a major cause for climate change, freshwater depletion, deforestation, and pollution of ecosystems, for example through over-application of fertilizers,' says Dr Marco Springmann of the Oxford Martin Programme on the Future of Food and the Centre on Population Approaches for Non-Communicable Disease Prevention at the Nuffield Department of Population Health, University of Oxford, who led the study.
'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.'
The
study 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 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 fertilizers for more
than 150 countries.
The
results showed various trade-offs. 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.
Improving
body weight by addressing the over- and under-consumption of calories led to
similar reductions in chronic disease mortality, due to reductions in levels of
overweight in high and middle-income countries, and reductions in levels of
underweight in low-income countries. However, it only moderately improved
nutrient deficiencies and led to small reductions in environmental impacts at
the global level, with reduced impacts in high and middle-income countries
balanced by increased resource use in low-income countries.
Adoption
of healthy, energy-balanced and predominantly plant-based dietary patterns
addressed these problems and 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. Globally, the changes
included large reductions in greenhouse gas emissions (54–87%) with greatest
reductions for vegan diets, medium-level reductions in nitrogen application
(23-25%) and phosphorus application (18–21%) with greatest reductions for vegan
diets, and small to moderate reductions in cropland use (8-11%) and freshwater
use (2–11%) with greatest reductions for pescatarian and flexitarian diets,
respectively.
'Our
research suggests that we need a dietary-change strategy that encourages
predominantly plant-based diets and improvements in weight levels and total
calorie intake, in line with the latest scientific evidence on healthy eating,
if we are to address nutrient deficiencies, lower the number of deaths from
chronic-diseases, and reduce environmental impacts,' says Dr Springmann.
'However,
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. Updating national dietary guidelines to reflect
the latest evidence on healthy eating is important not only for improving human
health, but also for preserving the health of the environment by reducing the
environmental impacts of our food system.'
