Study shows global shift towards an ultra-processed diet

The core message of the study can be summarised quite simply: across the globe, traditional,  scratch-cooked meals are gradually being replaced by diets composed largely of industrially manufactured foods. These are products that you don't simply make yourself, which often undergo several processing steps and often contain added flavourings, colourings or other additives. Examples include fruit yoghurts, cakes, sausages and supermarket-ready lasagne. “We are shifting towards an ultra-processed diet,” says nutrition researcher Neha Khandpur of Wageningen University & Research (WUR), who contributed to the publication. “And that pattern is associated with negative health outcomes.”

The researchers analysed sales data from 93 countries and food diaries from nine countries, ranging from Brazil to the United States. In nearly all regions, the sale of ultra-processed foods (UPFs) has been rising for years. Low- and middle-income countries in particular show a rapid increase.

In Spain, the share of daily energy intake from UPFs rose from eleven to almost 32 per cent in three decades; in Brazil from roughly ten to twenty per cent. Yet, these figures remain modest compared with the United Kingdom, Canada and the United States, where more than half of all calories consumed now come from UPFs. Although the Lancet study did not track the trend in the Netherlands, a Dutch study from 2022 showed that Dutch consumers also obtain more than half of their energy intake from UPFs.

A separate group of researchers compared the nutrient composition across fourteen countries. This shows that people who consume many UPFs typically ingest more total fat, saturated fat and added sugars, and less fibre, protein and potassium. “That makes it more challenging to meet the nutritional guidelines for several of these nutrients,” says Khandpur.

This dietary imbalance also appears to affect health. The researchers reviewed more than a hundred existing epidemiological studies on food patterns and risk of disease. Each study reflected data from tens to hundreds of thousands of people over long periods of time. Based on these studies, the authors conclude that there are consistent associations between high UPF intake and chronic conditions such as obesity, type 2 diabetes, cardiovascular disease and mortality. 

These are observational findings, the authors emphasise. The study does not prove that one factor directly causes the other. “Association is not the same as cause and effect,” Khandpur explains. “But when studies in different countries, in different populations and using different research methods all point in the same direction, we simply cannot ignore such a strong pattern.”

Much uncertainty remains about the precise mechanisms through which UPFs affect health. Researchers do know that many of these processed foods are energy-dense and less satiating. As a result, diets high in UPFs tend to provide more kilocalories than a kitchen-based diet. People also tend to eat these products more quickly, partly due to their structure and texture, leading to larger portion sizes. Other mechanisms may also play a role, but evidence is still limited. “It is unlikely that a single mechanism is to blame,” says Khandpur. “It is more likely a combination of factors reinforcing each other: the imbalanced nutrition composition, the structure, the pace at which you eat them, and the degree to which they displace whole foods.”

Processing itself is not inherently bad. Fermented foods such as tempeh, yoghurt and certain cheeses can actually contribute to health. Moreover, some products are processed specifically to reduce saturated fat or lower their energy density compared with traditional alternatives. Processing can also make food safer by removing harmful substances, increase bioavailability of nutrients and extend shelf-life and thus preventing food waste. 

Given their convenience, pleasant taste and attractive appearance, UPFs are unlikely to disappear from daily life. Nor do they have to, according to Khandpur. If people were to reduce their consumption of ultra-processed products in their diets to the level of the lowest one-fifth of consumers, the number of diets with too little fibre or too much energy, sugar or saturated fat would decrease significantly. In Canada, inadequately balanced diets would decrease by nearly seventy per cent; in the United States by more than ninety per cent. This shows that even small shifts in consumption could greatly improve the average diet.

“But we cannot place that responsibility solely on individual consumers,” the WUR researcher stresses. “In a food environment that is so complex and so tempting, you cannot expect people to always make the healthiest choice. That requires policy and innovation.” Research can help steer those efforts. At WUR, for example, scientists study how texture, mouthfeel and eating speed influence portion size and total food intake. They also investigate how everyday food environments shape consumer decisions. Such insights can help develop new products that are healthier and less likely to encourage overconsumption than current ultra-processed foods.

International organisations are now taking the issue seriously. UNICEF published a report on UPFs and child health this month, and the World Health Organization (WHO) is working on new guidelines and objective tools to help identify ultra-processed products.

There are currently no real guidelines or quality labels for UPFs in the Netherlands. For those wishing to make more conscious dietary choices, Khandpur recommends using the Dutch dietary guidelines or the Nutri-Score. “Nutri-Score was not designed with UPFs in mind, but it provides guidance and helps you make healthier choices.”

• Read the article in The Lancet: "Ultra-processed foods and human health: the main thesis and the evidence"