Ultra-processed diets drive obesity and climate change — but solutions are within reach

Diets around the world dependent on ultra-processed foods and animal-based agriculture are driving obesity rates and climate change, but solutions exist that would bolster health, and save money and the planet, according to a new review. 

The authors of the new paper, published in Frontiers in Science, point out that obesity rates have nearly tripled around the world over the past 50 years and roughly half of the people on the planet are expected to be either overweight or obese within the next decade. They argue that the rise in weight-loss drugs and surgeries do not address the root causes of global weight gain. 

However, countries can address the “twin crises” of obesity and climate change by focusing on the food system as a whole, incentivizing healthier eating and discouraging the consumption of heavily processed foods such as sugary drinks, bacon, hot dogs, lunch meats, many frozen foods, chips, candy and other snacks. 

“Both climate change and obesity are driven by unsustainable, but profitable, consumption,” the authors write. “Solutions exist but have not been adequately implemented owing to a lack of political will.” 

Researchers examined available evidence that links both obesity and climate change to a food system that relies heavily on animal agriculture and processing, which encourages over-consumption and poor health. Currently, about 38% of people globally suffer from excessive weight or obesity. 

“The global increase in obesity since the 1980s has been the most rapid and dramatic change in the human phenotype throughout our entire evolution,” the authors write.

“The global increase in obesity since the 1980s has been the most rapid and dramatic change in the human phenotype throughout our entire evolution.” 

While several factors contribute to obesity rates, including people becoming less active, the review finds that excess calories often in the form of processed foods are largely behind the obesity increase, especially in the US, where people consume on average more than half of their daily calories from ultra-processed foods. Such foods are linked to heart problems, diabetes and some cancers in addition to obesity.

The rise in ultra-processed foods and animal agriculture drives climate change as well, the review finds. Growing, processing, packing and transporting food accounts for roughly a third of the planet’s greenhouse gas emissions annually, with grazing livestock the largest contributor.

Ultra-processed foods such as processed meats drive up demand for livestock — and many other processed foods rely on large amounts of certain crops like corn, soy or palm oil, which are often grown in uniform fields with large amounts of pesticides and fertilizers.

This “large-scale monoculture of crops required for producing ultra-processed foods” furthers climate change via land clearance, degradation and biodiversity loss, the authors write.

“The most economically efficient way of ensuring we address these huge issues is a stop to subsidies for meat, energy-dense ultra-processed foods, and sugar in beverages,” said senior author Jeff Holly, an emeritus professor of clinical science at the University of Bristol, UK. “However, we are in a situation where these changes are politically very difficult.” 

The new review comes a month after a series of papers published in The Lancet, along with a related editorial, called for a “well resourced, coordinated global response” to “break the grip of the [ultra-processed foods] industry on food systems worldwide.”

Tackling both obesity and climate change 

Holly and colleagues say solutions to both problems are intertwined and need to focus more on the entire food system and less on the behavior of individuals, which “is no match for aggressive marketing campaigns,” said co-author Katherine Samaras from St Vincent’s Hospital Sydney, the Garvan Institute of Medical Research, and UNSW Sydney in a statement. 

“Although treatments such as medicines and surgeries offer important therapeutic options for individuals, they won’t substitute for tackling our unhealthy, unsustainable food and living environments,” she added.

The researchers put forth several recommendations to tackle obesity and climate change, including taxing certain ultra-processed foods and sugary drinks; subsidizing healthy foods with the taxes from unhealthy food; labeling and restrictions on marketing unhealthy foods to children; shifting diets toward more plant-based foods and fewer animal products.

“All of the data that are emerging from countries that have introduced taxes on sugar-sweetened beverages and front-of-food warning labels indicates that these system-level policies are resulting in reductions in population level consumption of these harmful foods and reductions in body mass index (BMI), particularly among children,” Holly said.

Such changes would not only reduce obesity and climate change but save money. Healthcare costs related to obesity are expected to reach more than $4 trillion within the next decade, while costs related to climate change could climb as high as $38 trillion annually over the next 25 years. 

US action on ultra-processed foods 

The review comes as US regulators are looking to define and potentially label ultra-processed foods, despite significant pushback from the food industry. The US Food and Drug Administration (FDA) and the US Department of Agriculture (USDA) solicited public input from July through October to help establish a uniform definition of ultra-processed foods. The issue is central to the “Make America Healthy Again,” or MAHA, movement and Health and Human Services Secretary Robert F. Kennedy Jr., who frequently points to such foods as a key driver in childhood diseases. 

In giving feedback, food and health advocates encouraged the agencies to to define ultra-processed foods through a lens of public health, while several food industry groups gave feedback that pushed back against the need to define ultra-processed foods at all, saying it will create confusion and unfairly target some foods.

“[Ultra-processed foods] simply are not a consistent or reliable proxy for the impact of different foods on human health. The term remains vague and contested, and using it as the basis for regulation would not strengthen nutrition programs,” the National Association of Convenience Stores wrote to the FDA.

Public comments closed in October and the FDA hasn’t yet announced a new definition. At a Washington, DC, summit on ultra-processed foods earlier this month, Kyle Diamantas, the FDA’s deputy commissioner for human foods, said “defining ultra-processed foods and tackling these issues is a priority” for the Trump administration. 

“It’s not something that we can solve alone at FDA,” he added. “This is something that will take a societal movement to continue to advocate for.”

Featured image: Ryan Collins/Unsplash+