Researchers on Wednesday cautioned that the growing worldwide intake of ultra-processed foods (UPFs) presents a serious health risk, urging governments to consider marketing restrictions and taxes on certain products produced by large food corporations.
The international team of scientists also defended their research against critics, comparing efforts to cast doubt on UPFs’ risks to the tactics once used by the tobacco industry to downplay health dangers.
While the definition of UPFs has sparked debate in scientific circles, with some experts calling for more precise criteria and further studies, leading researchers argue the evidence is already strong enough to demand action.
In a trio of studies published in The Lancet, the researchers reviewed 104 prior investigations and found that diets high in UPFs are linked to a significantly higher risk of obesity, diabetes, heart disease, and premature death.
Their second study highlighted that UPF consumption is on the rise globally, now accounting for more than half of daily calorie intake in countries including the United States, Australia, and the UK.
The third study pointed to a handful of multinational corporations for reshaping diets worldwide, promoting products made with cheap, industrial ingredients through aggressive marketing strategies.
In 2021, just eight major UPF companies—Nestlé, PepsiCo, Unilever, Coca-Cola, Danone, Fomento Económico Mexicano, Mondelez, and Kraft Heinz—controlled 42% of the industry’s $1.5 trillion in assets.
The authors recommended that countries introduce warning labels, limit marketing (especially targeting children), and tax selected UPFs, using the revenue to make fresh, healthy food more accessible for low-income families.
Are there healthy UPFs?
The researchers said they welcomed “valid scientific criticisms” of the Nova classification system developed by Brazilian epidemiologist Carlos Monteiro, the lead author of the first study.
The Nova system, which separates food into four categories from the least to most processed, has come under scrutiny for not taking into account nutrients known to be unhealthy such as fat, salt and sugar.
This has meant that food traditionally thought to be healthy — such as fake meat products, plant-based milks and some breads and canned vegetables — could be considered ultra-processed.
The researchers acknowledged the important role played by fat, salt and sugar, calling for future research to isolate the effect of ultra-processing in foods such as flavoured and plain yoghurts.
Almost all existing UPF research reviewed by the team was observational, which means it cannot directly establish cause and effect.
The precise mechanism for how UPFs cause such a wide range of health problems also remains unclear.
The researchers laid out numerous theories, including that UPFs contain a higher density of calories than fresh food, provoke overeating by combining elements such as fat and sugar, can be consumed more quickly because they are softer, or potentially contain harmful additives.
Beyond time to act
Chris van Tulleken, a co-author of the second paper and author of the bestselling book “Ultra-Processed People”, accused scientists who have criticised UPF research of often having ties to the food industry.
“We see tobacco industry tactics playing out this morning, in fact, while we’re on this call,” he told an online press conference on Tuesday.
The second paper’s lead author, Phillip Baker of the University of Sydney, accused the UPF industry of “targeting the scientists, and the science, attempting to manufacture scientific doubt”.
Hilda Mulrooney, a nutritionist at Kingston University London, not involved in the research, told AFP the team made a compelling case.
“Clearly, the authors of these papers are predisposed in favour of Nova since they created it,” she said, adding that more research is needed to identify the exact mechanisms that UPFs could be causing harm.
However, “given the disproportionate risks of chronic disease to the most disadvantaged groups and the costs of a poor diet to individuals, healthcare systems and finances, it is beyond time to act” on UPFs, she said.