Junk food for thought: Landmark Canadian study directly links ultra-processed foods to poor health
McMaster University
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Study authors Angelina Baric and ASnthea Christoforou, Department of Kinesiology at McMaster University, found ultra-processed foods are directly and significantly to poor health outcomes.
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A landmark study exploring Canadians’ consumption of chips, frozen pizzas, breakfast cereals and other ultra-processed foods typically loaded with fat, sugar and additives has confirmed these foods are directly and significantly linked to poor health outcomes.
Researchers at McMaster University investigated the relationship between ultra-processed food (UPF) consumption and risk factors including blood pressure, cholesterol levels (LDL and HDL), waist circumference and body mass index (BMI).
Their study is the first in Canada to leverage population-based and robust biomarker data to examine this relationship.
The team analyzed data from more than 6,000 adults across Canada, representing a diverse range of ages, health conditions and socio-economic backgrounds. The subjects completed a questionnaire for the Canadian Health Measures Survey, conducted by Health Canada and Statistics Canada, and were then personally assessed at mobile clinics.
Individuals who consumed the most UPF were more likely to be men, and to have lower income levels, less education and to have reported lower fruit and vegetable intake. They had significantly higher BMI, waist circumference, blood pressure, insulin, and triglyceride levels than those who consumed the least UPF.
Researchers noted that many links between UPF consumption and cardiometabolic risk factors remained significant even after adjusting for BMI, suggesting that ultra-processed foods may influence health through mechanisms beyond weight gain, such as inflammation, insulin resistance, and poor metabolic regulation – all well-established predictors of heart disease and type 2 diabetes.
The associations persisted even after adjusting for physical activity, smoking, the total amount of food consumed and socioeconomic factors including income and education.
“We have this very complex food supply that is more than just the nutritional composition of a food,” explains Anthea Christoforou, an assistant professor in the Department of Kinesiology at McMaster University and senior author of the paper.
“It may be about the additives. The way the food is prepared. It's related to the packaging and the marketing of that food. All these things come together to create this food environment that really affects the healthfulness of our diets.”
The study, published today in the journal of Nutrition and Metabolism, uncovered a strong association between UPF consumption and the presence of C-reactive protein (CRP), which the liver produces in response to inflammation, as well as an increase of white blood cells.
“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,” says Christoforou.
UPFs are ready-to-eat, pre-packaged foods, often high in sodium, sugar and unhealthy fats, while being low in fibre, minerals and vitamins. They are often more convenient, heavily marketed, and appeal to time-pressed consumers, factors that may contribute to higher consumption among lower-income groups and growing health disparities.
Researchers point out that such foods have come to dominate the global food supply, particularly in middle- and high-income countries. Canadian study participants consumed an average of more than three servings of UPFs per day, but those who consumed the highest amounts averaged six servings daily, and researchers believe UPFs may be replacing healthier foods such as fruits and vegetables.
"Ultra-processed foods are impacting health across all socioeconomic groups," says Angelina Baric, a graduate student in the Department of Kinesiology at McMaster and co-author of the study. "While some populations are more exposed to these foods, our findings show that the health risks persist independently of income and education. This highlights the need for broad, equitable food policies that protect everyone."
Health Canada currently recommends reducing the consumption of processed foods as part of its healthy eating guidelines and has begun consultations to develop broader strategies for limiting UPFs in the Canadian food supply.
“We found consistent evidence that eating ultra-processed foods is associated with cardiometabolic risk factors, which not only reinforces the evidence we have seen linking these foods with rising overweight and obesity rates in Canada and other parts of the world, but also provides more detailed information about what’s happening in the body before a full disease,” says Baric.
In future, the research team plans to develop a study on children’s eating habits as related to processed foods, and female health, focusing on fertility, menses and the onset of menopause.
They are also investigating the biological mechanisms by which UPFs may trigger inflammation and metabolic dysfunction and exploring the role of affordability and food environments in driving UPF consumption — with the aim of informing more equitable public health strategies.
Journal
Nutrition and Metabolism
Method of Research
Data/statistical analysis
Subject of Research
People
Article Title
Ultra-processed food consumption and cardiometabolic risk in Canada: a cross-sectional analysis of the Canadian Health Measures Survey
Article Publication Date
6-May-2025
COI Statement
All authors contributed to the study conception and design. Material preparation and analysis were performed by AB and AC. AB wrote the first draft of the manuscript with input from AC and VSM. All authors read and approved the final manuscript. AC supervised the project. Corresponding author: Angelina Baric, barica1@mcmaster.ca
Eating ultra processed foods may speed up early signs of Parkinson's disease
MINNEAPOLIS — People who eat more ultra processed foods like cold breakfast cereal, cookies and hot dogs are more likely to have early signs of Parkinson’s disease when compared to those who eat very few ultra processed foods, according to a study published in the May 7, 2025, online in Neurology®, the medical journal of the American Academy of Neurology. The study does not prove that eating more ultra processed foods causes early signs of Parkinson’s disease; it only shows an association.
Researchers looked for signs of prodromal Parkinson’s disease, which is the earliest stage, when neurodegeneration begins, but more characteristic symptoms of Parkinson’s disease, like tremors, balance problems and slow movement, have not yet begun. These early symptoms can begin years or even decades before the typical symptoms start.
“Eating a healthy diet is crucial as it has been associated with a lower risk of neurodegenerative diseases and the dietary choices we make today can significantly influence our brain health in the future,” said study author Xiang Gao, MD, PhD, of Institute of Nutrition, Fudan University in Shanghai, China. “There's growing evidence that diet might influence the development of Parkinson's disease. Our research shows that eating too much processed food, like sugary sodas and packaged snacks, might be speeding up early signs of Parkinson's disease.”
The study included 42,853 people with an average age of 48 who did not have Parkinson’s disease at the start of the study. They were followed up to 26 years.
Participants had regular medical exams and completed health questionnaires. Researchers reviewed results to determine if they had early signs of Parkinson’s disease, including rapid eye movement sleep behavior disorder, constipation, depressive symptoms, body pain, impaired color vision, excessive daytime sleepiness and reduced ability to smell.
Participants completed a food diary every two to four years, listing what they ate and how often.
Researchers looked at several types of ultra processed foods including sauces, spreads, or condiments; packaged sweets; snacks or desserts; artificially or sugar-sweetened beverages; animal-based products; yogurt or dairy-based desserts; and packaged savory snacks. One serving was equivalent to a single can of soda, one ounce of potato chips, one slice of packaged cake, a single hot dog or one tablespoon of ketchup.
Researchers calculated how many ultra processed foods participants ate on average per day.
They divided participants into five groups. The highest group ate 11 or more servings of ultra-processed food per day on average. The lowest group ate an average of fewer than three servings per day.
After adjusting for factors such as age, physical activity and smoking, researchers found that participants who ate 11 or more servings of ultra processed foods per day had a 2.5-fold higher likelihood of having three or more early signs of Parkinson’s disease compared to those consuming fewer than three servings per day.
When looking at individual early signs of Parkinson’s disease, researchers also found that eating more ultra processed foods was tied to an increased risk for nearly all symptoms except constipation.
“Choosing to eat fewer processed foods and more whole, nutritious foods could be a good strategy for maintaining brain health,” said Gao. “More studies are needed to confirm our finding that eating less processed food may slow down the earliest signs of Parkinson's disease.”
A limitation of the study was that the amount of ultra processed food consumed was self-reported, so participants may not have remembered accurately how much and what specific foods they ate.
The study was supported by the National Institute of Neurological Disorders and Stroke, the municipal public health system in Shanghai, China, the National Natural Science Foundation of China and the China Postdoctoral Science Foundation.
Discover more about Parkinson’s disease at BrainandLife.org, from the American Academy of Neurology. This resource also offers a magazine, podcast, and books that connect patients, caregivers and anyone interested in brain health with the most trusted information, straight from the world’s leading experts in brain health. Follow Brain & Life® on Facebook, X, and Instagram.
The American Academy of Neurology is the leading voice in brain health. As the world’s largest association of neurologists and neuroscience professionals with more than 40,000 members, the AAN provides access to the latest news, science and research affecting neurology for patients, caregivers, physicians and professionals alike. The AAN’s mission is to enhance member career fulfillment and promote brain health for all. A neurologist is a doctor who specializes in the diagnosis, care and treatment of brain, spinal cord and nervous system diseases such as Alzheimer's disease, stroke, concussion, epilepsy, Parkinson's disease, multiple sclerosis, headache and migraine.
Explore the latest in neurological disease and brain health, from the minds at the AAN at AAN.com or find us on Facebook, X, Instagram, LinkedIn, and YouTube.
Journal
Neurology
