Chips, frozen pizza, sugary cereal. They’re fast, convenient, and sometimes feel like the only option in a busy day. But a new study out of McMaster University suggests these ultra-processed foods (UPFs), aka junk food, are doing more than just nudging up your belt size—they may be quietly rewiring your body’s inner workings in ways that’ll lead to significant negative health outcomes and long-term inflammation.
Published in Nutrition & Metabolism, the study linked UPF consumption with biological health markers on a national scale. Researchers analyzed data from more than 6,000 Canadian adults across a range of ages, health backgrounds, and income levels. Participants completed detailed dietary questionnaires and then underwent in-person health assessments through Health Canada’s mobile clinics.
What Are Ultra-Processed Foods?
UPFs are the kinds of foods you often find in boxes, wrappers, or plastic trays. They’re shelf-stable, quick to prepare, and designed to taste great with minimal effort. They’re typically high in salt, sugar, and unhealthy fats, and low in fiber, protein, and micronutrients.
Those who consumed the most UPFs had significantly higher blood pressure, insulin, triglycerides, BMI, and waist circumference. But even when researchers adjusted for weight and calorie intake, the links to poor health didn’t go away.
“These two biomarkers indicate that these foods are causing an inflammatory response in our bodies. In a sense, this suggests that our bodies are seeing these as non-foods, as some kind of other element,” explained author Anthea Christoforou.
The study also found a consistent connection between high UPF intake and elevated levels of C-reactive protein (CRP)and white blood cells—both signs of chronic inflammation. These are the kinds of biological changes that often precede chronic diseases like heart disease and type 2 diabetes.
Interestingly, the highest UPF consumers weren’t just those with the least time or money, though those factors did play a role. While individuals with lower income and education levels tended to consume more ultra-processed foods, the health risks persisted across all groups.
“Ultra-processed foods are impacting health across all socioeconomic groups,” said co-author, Angelina Baric.“While some populations are more exposed to these foods, our findings show that the health risks persist independently of income and education.”
“We found consistent evidence that eating ultra-processed foods is associated with cardiometabolic risk factors,” Baric said.
In short, there is no hiding or running from it, and the evidence is becoming clearer and clearer by the day and that is UPF is damaging your health and the health of our country. We need policies that decrease people’s exposure to UPF and increase exposure and accessibility to whole, nutritious foods.
Angelina Baric et al, Ultra-processed food consumption and cardiometabolic risk in Canada: a cross-sectional analysis of the Canadian health measures survey, Nutrition & Metabolism (2025). DOI: 10.1186/s12986-025-00935-y
