Ultra-processed foods include reconstituted meat products such as sausages, ready meals, margarines, confectionery, soft drinks, sugary cereals, packaged baked goods and snacks, and other food and beverages that contain artificial additives like sweeteners and flavours.
High consumption of these food types has long been linked to negative health outcomes and higher risk of obesity, cardiovascular disease, diabetes, high blood pressure, high cholesterol and some cancers. But there has previously been very little understanding of the impact a diet high in ultra-processed foods has on planetary health.
A new study, published yesterday in the journal The Lancet Planetary Health, has now linked ultra-processed foods with increased environmental impact.
“This study shows for the first time how increasing the consumption of ultra-processed foods has produced more greenhouse gas emissions and used more water and land, even in developing countries like Brazil,” said Dr Ximena Schmidt, co-author and Global Challenges Research Fellow at the Centre for Sustainable Energy Use, Brunel University London.
Ultra-processed foods the ‘largest contributor’ to environmental impact
Looking at dietary patterns in Brazil, the international research international collaboration behind the study contend that ultra-processed foods have been the ‘largest contributor’ to worsening impacts on the country’s food-related greenhouse gas emissions, the nation’s water footprint and ecological footprint, such as deforestation.
The study used nationally representative data over a 30 year time-frame to demonstrate how changes in a nation’s diet can affect its contribution to climate change.
Researchers from the University of São Paulo, City University of London, the University of Manchester, Brunel University London, and the University of Sheffield used household budget survey data taken from urban Brazilian households between 1987 to 2018.
They calculated the environmental impact of food items purchased per 1,000 calories consumed for the four food groups outlined by the widely used NOVA system: unprocessed/minimally processed foods; processed culinary ingredients; processed foods; and ultra-processed foods.
The study found that while the proportion of unprocessed food and processed culinary ingredients in the households’ diet had decreased, the amount of processed and ultra-processed foods consumed had increased. It found that the increasing environmental impact of ultra processed foods was driven by an increase in consumption of ultra-processed meat, which at least doubled its contribution to daily environmental impacts per individual, reaching about 20% of total diet-related footprints over the 30-year time-frame.
Per 1,000 calories consumed, these changes in the diet were associated with a 21% increased contribution to greenhouse gas emissions, 22% increased contribution to the nation’s water footprint and 17% increased contribution to its ecological footprint.
Dr Schmidt said the findings underlined the impact that our dietary choices have on our environmental impact. “We need to help people change their diets to protect the environment and live healthy lives. We need to finally acknowledge that impacts to the environment and health have to be tackled together."
Economic development linked to rise in ultra-processed diets
The study’s authors suggested that the nutrition transition towards diets that are higher in ultra-processed foods over the last 30 years in Brazil is a change that echoes dietary shifts in the UK.
The experts argue that Britain went through a similar nutrition transition over the last 100 years. As emerging economies continue to grow, so will trends in the consumption of ultra-processed foods, the predicted.
Ultimately, this could adversely affect their ability to meet climate change targets.
“For our health and sustainability, ultra-processed foods are already a massive, and growing problem. This study shows that Brazil is experiencing a similar transition in their diet to what has happened in the UK. Both in a shorter time frame, and with similar large effects on the environment,” noted study co-author Dr Christian Reynolds, a Senior Lecturer at the Centre for Food Policy, City, University of London.
Dr Reynolds believes that policy intervention is needed to limit the negative consequences that ultra-processed food consumption will have on the health of planet and people.
“Our findings suggest that diet-related diseases and climate change share an underlying driver and therefore, should be addressed simultaneously. Multicomponent actions and policies targeting multiple areas should be considered. For instance, fiscal interventions such as taxes or subsides, regulation on advertising, and improving food and menus labelling with the addition of environmental impacts,” the food policy expert suggested.
Food and climate: Unpicking a ‘complex’ relationship
Food and agriculture sit at an unhappy intersection. Climate change is a significant threat to the future of the food sector, which is also a big contributor to the greenhouse gas emissions that are driving global heating.
The food system is linked to 35% of total manmade greenhouse gas emissions, according to one study published last month. Meat and dairy products, including the crops grown to feed livestock and pastures for grazing, contribute 57% of emissions linked to the food system, the carbon mapping research suggested. Raising plant-based foods for human consumption contributes 29%, with the remaining 14% linked to products not used as food or feed, such as cotton and rubber.
At the same time, food producers are on the front line of climate change. Extreme weather, swings in precipitation patterns and changes in temperature are felt by farming communities around the world, negatively impacting yields and livelihoods.
Pointing out this conundrum nutritionist and study first author Jacqueline Tereza da Silva, of the Department of Preventative Medicine University of São Paulo, characterised the link between food production, consumption and climate as ‘complex’ in nature.
"The relationship between food systems and climate change is complex and challenges food security itself. Food systems are responsible for a third of global greenhouse gas emissions, and yet, at the same time, they suffer from the climate impacts that they themselves help to cause,” the academic observed.
‘Greenhouse gas emissions, water footprint, and ecological footprint of food purchases according to their degree of processing in Brazilian metropolitan areas: a time-series study from 1987 to 2018’
Authors: Jacqueline Tereza da Silva, MSc; Josefa Maria Fellegger Garzillo, PhD; Fernanda Rauber, PhD; Alana Kluczkovski, PhD; Ximena Schmidt Rivera, PhD; Gabriela Lopes da Cruz, MSc; Angelina Frankowska, PhD; Carla Adriano Martins, PhD; Maria Laura da Costa Louzada, PhD; Prof Carlos Augusto Monteiro; Christian Reynolds, PhD; Prof Sarah Bridle; Renata Bertazzi Levy, PhD
The project was funded by the Science and Technology Facilities Council Global Challenges Research Fund (STFC GCRF).