The science and politics behind the panic over ultra-processed foods

Ultra-processed foods have a terrible reputation.

Studies have linked them to several chronic diseases. Journalists and health influencers call them poison. Some public health experts are calling for a global halt to their production and consumption.

But the debate around ultra-processed foods is not as settled as it seems. As a researcher who studies social movements for healthy, sustainable eating, I have documented the history of processed foods and examined debates around the science and politics of ultra-processing.

Simply put, ultra-processed foods are mass-produced industrial formulations that use ingredients not typically found in a home kitchen and typically contain little or no intact whole foods.

However, the very definition of ultra-treaty is highly contested. While a growing number of supporters say ultra-processing is dangerous to public health, skeptics counter that the fervor around the topic has become a moral panic and insist that some ultra-processed foods can be part of a healthy diet.

A Brief History of Food Processing

People have been processing food – that is, turning crops and animals into food ingredients and products – for all of human history. Cooking, which historians generally consider the earliest form of food processing, dates back 2 million years. Over the ensuing millennia and centuries, humans developed and perfected other traditional methods of food processing, including grinding, cooking, fermenting, drying and pressing.

New types of food processing were created in the industrial age, beginning in the mid-18th century. Canning, pasteurization, and refrigeration are among the major innovations that have transformed not only the way people eat, but society as a whole.

Before that time, almost all food was local food – that is, produced within a radius of a few dozen kilometers – and people quickly consumed fresh food to prevent it from spoiling. Food processing promised to improve food safety, shelf life, quality, convenience, taste and health. The world became urbanized as regional and international supply chains expanded. Geographically dispersed farmers were connected to retailers and consumers through the new modern food system.

From the mid-20th to the 21st century, food manufacturers added a host of complex technological innovations to the food processing playbook. Their efforts made processed foods more standardized for the mass market and more convenient for consumers. But public health experts have warned that processed junk food is full of salt, sugar and saturated fat – problematic nutrients linked to obesity, diabetes and other diet-related illnesses.

Food processing and the NOVA framework

In the mid-2000s, some healthy eating advocates began arguing that the nature and extent of food processing, rather than the presence of specific problematic nutrients, explained diet-related chronic diseases. Journalist Michael Pollan implored his audience to avoid “edible, food-like substances.” Instead, he advised, “Eat food. Not too much. Mostly plants.”

Brazilian epidemiologist Carlos Monteiro coined the term “ultratreatment” in 2009 as part of his work on what he and his colleagues called the NOVA classification. The NOVA framework establishes a four-category system that characterizes a food based on its level of processing.

NOVA 1 category includes unprocessed or minimally processed plant or animal foods that are close to their natural state and contain no additives. Category 2 refers to processed culinary ingredients, that is, products derived from Category 1 by pressing, grinding or similar techniques. Category 3 describes processed foods made by combining Category 1 and Category 2 using traditional methods, such as baking, boiling, or canning.

NOVA Category 4 foods are ultra-processed foods, often described as industrially manufactured food products that cannot be prepared at home. Examples of ultraprocessing include the separation of whole foods into substances, the chemical formulation of foods, or the use of cosmetic additives such as food colorings.

Under this framework, companies design ultra-processed foods to be convenient, hyper-palatable, and highly profitable. They are attractively packaged, heavily marketed, and intended to supplant other food groups.

Today, ultra-processed foods represent an increasingly important part of the world’s diet. They account for more than 50% of total calories in the United States, followed closely by many low- and middle-income countries.

An unstable science

Since the emergence of the NOVA framework, researchers have attempted to test whether food processing could explain how certain foods affect people’s health.

The vast majority of this work has explored the correlations between the consumption of ultra-processed foods and the development of health problems. One consistent finding stands out: people who eat more ultra-processed foods are at higher risk of developing multiple chronic diseases and dying prematurely.

However, even this conclusion is more complex than it seems. It turns out that certain categories of ultra-processed foods — like sugary drinks like soda and processed meats like deli meats — are consistently associated with negative health effects, including heart disease and stroke. But other ultra-processed products—breads, cold cereals, yogurt, and even salty snacks—have actually been correlated with lower rates of these health problems.

Other ultra-processed foods—including sauces, condiments, and ready-to-heat meals like frozen meals—show no consistent link to people’s health, one way or the other.

Only a handful of clinical trials that can truly demonstrate cause and effect have explored the health effects of ultra-processed foods. One large study found that participants who ate a diet of ultra-processed foods for two weeks consumed more calories and gained more weight than participants who ate a minimally processed diet, but other experiments found no clear effect. Additionally, these studies typically only last a few weeks – far too short a time frame to draw conclusions about long-term health impacts.

A delicate definition

Some food science researchers are not surprised by these mixed results, arguing that the definition of “ultra-processed” is ambiguous and often subjective. For example, a cake made by an amateur baker would be considered a NOVA Category 3 “processed food.” But if that same cake were manufactured industrially using a commercial preservative, then packaged and sold in a grocery store, it would become a NOVA Category 4 “ultra-processed food” — even if the two cakes were nutritionally identical.

Basically, many nutrition scientists aren’t convinced that processing alone can explain why certain foods are associated with poor health. Instead, they point out that unhealthy ultra-processed foods often have poor nutritional profiles and other qualities that make them easy to overeat. And they argue that making ultra-processed foods healthier, without eliminating them completely, can improve public health.

Vilifying ultra-processed foods can have harmful effects, they suggest, such as creating unnecessary fear and promoting eating disorders. It may also stigmatize eco-friendly, plant-based meats or ultra-processed products such as infant formula designed for clinical nutrition.

The mass rejection of ultra-processed foods could also make life more difficult for families who rely on the convenience and affordability of these products.

Processing versus nutrients

On the other hand, many food policy and public health researchers argue that the common definition of ultra-processed foods is clear enough, especially if exceptions are made for healthy ultra-processed foods. They also note that many supporters of ultra-processed foods have ties to the food industry. They insist that the existing evidence is strong enough to take immediate policy action, including changing the way ultra-processed foods are produced, purchased and marketed.

Regulating ultra-processed foods would not only benefit public health, advocates say. It could also help limit damage to food culture, businesses and the environment.

In this sense, ultra-processed foods are a symptom of a larger problem: an unsustainable industrial food system dominated by a handful of companies. Of course, this argument is also widely contested.

Ultimately, researchers and advocates of all stripes mostly agree that the modern food environment needs to be made healthier. The main point of disagreement, however, is whether policy development and food guidance should directly address ultraprocessing or instead stick to a more traditional focus on nutrients.