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Many ultra-processed foods, such as cakes and other baked goods, are high in sugar, salt and saturated fats.Credit: Elena Zaretskaya/Getty
Later this month, the United Nations General Assembly will discuss a proposal to eliminate trans-fatty acids (trans fats) from diets. These fats are mainly produced industrially. They clog up arteries, increasing people’s risk of a heart attack or death. Some 60 countries are already on a path to eliminating these fats and the World Health Organization has certified that 9 have removed industrially produced trans fats from their food supply.
Eliminating these fats will be a win. However, a coalition of public-health researchers and institutions in Europe and in low- and middle-income countries is urging countries to ensure that the language of the UN declaration refers specifically to industrially produced trans fats, which it doesn’t at present. This is because trans fats also occur in natural products, such as milk and other dairy products.
Are ultra-processed foods really so unhealthy? What the science says
In a letter coordinated by the International Livestock Research Institute, a non-profit organization based in Addis Ababa, and backed by the African Union, signatories say that nations need to be careful that the proposal does not inadvertently discourage foods that are important for nutrition, especially in poor countries. They are making an important point. Researchers have a responsibility to push for accuracy and precision and to reduce the possibility of unintended consequences in public-health policy.
The debate about trans fats feeds into a broader argument in the dietary science and policy field that is similarly rising up the global agenda. Industrially produced trans fats are a common component of ultra-processed foods — an umbrella term for products that are made using industrial ingredients and food extracts with additives. These food products are often high in salt, sugar and saturated fats. Latin America has been leading the world both in drawing attention to ultra-processed foods and in taking action to discourage their production and consumption given accumulating evidence of the links such products have to obesity and cardiovascular disease1.
Ultra-processed foods are an active area of study, but researchers are also debating what the term means and how to reduce the risk that its use will have unintended consequences2. It was described in a 2009 paper by Carlos Monteiro, a nutrition researcher at the University of Sao Paulo, Brazil3. Foods are categorized using a scale (called the NOVA classification system) that groups them according to the extent, type and reason of processing (see go.nature.com/4nbza72). At one end are minimally processed items that require relatively little processing, such as frozen vegetables and pasta. At the other end are ultra-processed foods, which contain products that you won’t find in most kitchens.
Eating ultra-processed foods could make it harder to lose weight
The study and the NOVA scale have had a considerable impact on health policy. The classification system, which is recognized by the UN Food and Agriculture Organization in Rome, has pushed many governments to develop strong public-health policies, often despite organized and sustained opposition from food conglomerates. Latin American countries, for example, are mandating warning labels and levying taxes on food products that are high in salt, sugar and saturated fat.
However, as we report in a News Feature, some researchers say that the NOVA scale has its limitations, because processing is only one factor that explains why people eat such foods and what effects they have on the body. Dietary habits are also influenced by palatability — there is some evidence that people are attracted to products that are easy to consume, such as soft-textured or fast foods, or include ingredients that can increase cravings. The number of calories per portion (energy density) also influences people’s dietary habits. Another difficulty with the scale is that the ultra-processed category also includes some varieties of bread and baby formula as well as hot dogs and chicken nuggets, even though the reasons for processing each of these products are different.
Too easy to swallow
The developers of the NOVA system agree that the act of processing on its own is not the issue, and that some forms — milk pasteurization to remove bacteria, for example, or the chilling or freezing of vegetables to prolong shelf life — are beneficial.
Governments and regulatory bodies need to be more aware of these issues, and there is a need to clarify the definition of ultra-processed foods and reduce the unintended effects of using a vague term. US health secretary Robert F. Kennedy Jr, one of the strongest critics of ultra-processed foods, has issued a call for a uniform definition so that there is consistency in research and policy. In the United Kingdom, the country’s main research funder, UK Research and Innovation, has commissioned several studies to test public awareness of and attitudes towards these foods, the results of which are due to be reported next year.
The 2009 study shone a much-needed spotlight on dietary changes, including the replacement of conventionally prepared meals with industrially produced foods. But there is a spectrum of dietary issues worldwide: obesity is a growing problem, but so is a lack of access to sufficient calories. This means that there cannot be a one-size-fits-all solution. Government intervention must ensure that the worst excesses of industrial food production are reined in, while ensuring the availability of appropriate food for all.
