Canadian study links UPFs to inflammation and metabolic dysfunction
A landmark study from McMaster University examined the diets and health markers of over 6000 Canadian adults. It found that individuals consuming the highest amounts of ultra-processed foods had significantly worse health profiles, including higher BMI, waist circumference, blood pressure, insulin, and triglyceride levels.
But the most concerning findings went deeper than weight gain. Researchers found strong associations between UPF intake and inflammation, as measured by elevated levels of C-reactive protein (CRP) and white blood cells.
“These two biomarkers indicate that these foods are causing an inflammatory response in our bodies,” said Anthea Christoforou, assistant professor at McMaster University and senior author of the study. “In a sense, this suggests that our bodies are seeing these as non-foods, as some kind of other element.”
Even after adjusting for income, education, physical activity, and total food intake, the correlations persisted. As Christoforou explained, “It may be about the additives. The way the food is prepared. It’s related to the packaging and the marketing of that food.”
Global meta-analysis finds dose-dependent rise in chronic disease risk
This Canadian data aligns with a global meta-analysis presented at the American College of Cardiology Asia 2025 scientific meeting. The analysis pooled data from over 8 million adults across 41 studies and found a clear dose-response relationship between UPF intake and adverse outcomes.
Each additional 100 g of UPFs consumed per day increased the risk of hypertension by 14,5%, digestive diseases by 19,5%, and all-cause mortality by 2,6%. Even small daily increases were linked to measurable harm.
“Ultra-processed foods are characterized by high sugar, high salt, and other non-nutritive components,” said Dr Xiao Liu of Sun Yat-sen University. “These products may contribute to adverse health outcomes through multiple mechanisms, including systemic inflammation, oxidative stress, and impairment of insulin sensitivity.”
Multinational mortality model estimates premature deaths linked to UPFs
Adding further urgency, a multinational study published in the American Journal of Preventive Medicine estimated the number of premature deaths attributable to UPFs across 8 countries. In the United States alone, UPFs were linked to 124.000 early deaths in 2018. The researchers found that for every 10% increase in a person’s dietary share of UPFs, the risk of death rose by 3%.
“This study shows that the attributable burden in high-income countries is currently higher, but it is growing in others,” said lead investigator Eduardo Nilson. “Policies that disincentivize the consumption of UPFs are urgently needed globally.”
More than a matter of willpower
Ultra-processed foods are engineered to be hyper-palatable, shelf-stable, and convenient. These features make them particularly appealing to time-strapped consumers, and disproportionately consumed by those with lower income or education levels. But researchers stress that this is not simply a matter of personal choice.
“We have this very complex food supply that is more than just the nutritional composition of a food,” said Christoforou. “All these things come together to create this food environment that really affects the healthfulness of our diets.”
In the McMaster study, even after accounting for socioeconomic status, the health risks linked to UPF intake remained. This suggests that everyone, not just disadvantaged populations, is vulnerable.
But can we define UPFs reliably?
One common criticism of UPF research is that it’s quite hard to define what UPFs are. The widely used NOVA classification categorises foods by processing level. But this results in some nutrient-fortified or convenient products to end up together with unhealthy items. These could be foods such as plant-based milks, wholegrain sandwich breads, packaged guacamole, protein powders, or dark chocolate with >70% cocoa.
Even the global meta-analysis acknowledged this limitation, noting that differing interpretations of UPFs between studies affected comparability. Critics also point out that observational studies can’t prove causation.
Still, the consistency and strength of the associations across multiple populations, even after adjusting for confounding variables, has researchers convinced. “Emerging evidence suggests a dose-response relationship,” said Liu. “The more ultra-processed foods consumed, the greater the health risk.”
What can be done?
Experts agree that reducing UPF intake, even modestly, can offer measurable benefits. They urge governments to support public health through clearer labelling, advertising restrictions, and subsidies for minimally processed foods.
“While some populations are more exposed to these foods, our findings show that the health risks persist independently of income and education,” said Angelina Baric, co-author of the McMaster study. “This highlights the need for broad, equitable food policies that protect everyone.”
Until then, each one of us can take action by choosing whole, minimally processed foods, cooking at home when possible, and carefully reading ingredient lists, even on foods marketed as healthy.
