A new study by researchers at McMaster University has found ultra-processed foods are correlated with obesity.
The findings align with what health experts are saying on the issue: that ultra-processed foods play a key role in Canada’s rising obesity rate.
“This is an emerging area of policy research, and I expect to see an increased focus on ultra-processed food-targeted policies,” said Daniel Zaltz, a postdoctoral researcher in the University of Toronto’s Department of Nutritional Sciences.
“The breadth of evidence shows the negative health impacts of diet patterns high in ultra-processed foods.”
Ballooning rates
Ultra-processed foods generally refer to industrially produced foods that contain ingredients not found in home kitchens.
“[Ultra-processed foods] often contain things that have a lot of flavour enhancers… [and] preservatives in there to make them more tantalizing,” said Chelsea Cross, a registered dietitian with Dietetic Directions.
They span a wide range of foods, from soda and chips to flavoured yogurts and commercially prepared breads.
“These things have a lot of extra sugar or a lot of extra fat or hidden sodium and stuff like that,” Cross said.
The McMaster study suggests ultra-processed foods are a big part of Canada’s growing obesity problem.
Nearly one-third of Canadian adults were obese in 2022, up from about one in five in 2003. Another third are overweight. A person is considered overweight with a Body Mass Index over 25, and obese with a BMI that exceeds 30.
The study found consistent associations between the consumption of ultra-processed foods and key markers of obesity, such as increased BMI and waist circumference. The study’s findings are consistent with similar studies in Canada, the U.S. and other countries. Other recent studies have also linked ultra-processed foods with certain cancers, such as colorectal cancer.
Angelina Baric, one of the McMaster study’s co-authors, says the health risks associated with these foods cut across different demographics.
“While some populations are more exposed to these foods, our findings show that the health risks persist independently of income and education,” Baric said in a media release announcing the study. “This highlights the need for broad, equitable food policies that protect everyone.”
Other recent studies have indicated the prevalence of these foods in the diets of Canadian youth and children.
A University of Toronto study published in February found Canadian preschoolers get nearly half of their daily calories from ultra-processed foods. And a University of Toronto study from last May found 70 per cent of the food sampled in Canadian school lunch programs served “pre-packaged, often processed foods high in nutrients of concern.”
‘Informed choices’
Currently, there are no regulations specifically targeting ultra-processed foods due to the difficulty of defining what foods qualify as “ultra-processed.”
“Reducing the volume of ultra-processed foods in the Canadian food supply is an uphill battle,” Zaltz said.
Instead, public health efforts to combat obesity centre primarily on the Canada Food Guide, a table of recommendations on a healthy diet. Health Canada has been publishing the guide since 1942 and periodically updates it.
The current version of the guide, which was last updated in 2019, recommends Canadians “limit highly processed foods,” and “prepare meals and snacks using ingredients that have little to no added sodium, sugars or saturated fat.”
Health Canada told Canadian Affairs it promotes the guide through various channels, including social media and marketing campaigns, conference presentations and public webinars, and youth education. Health Canada offers educators a food guide “toolkit” with lessons for children of various ages.
Zaltz says the guide is a “great starting point.”
He also noted many food policies are linked to the food guide. Experts in nutrition and health sciences “use its guidance to design targeted interventions, for example, ways to reduce added sugars, which is a specific recommendation in the guide.”
The Dietitians of Canada, a professional association for dietitians, also endorsed the guide in a statement to Canadian Affairs.
“By emphasizing vegetables, fruits, protein foods, and grains, and recommending limits on ultra-processed foods, the guide supports improved eating habits for a variety of dietary patterns and cultural preferences,” an association representative said in an emailed statement.
Regulatory changes
In 2026, Canada plans to take an additional step to tackle the risks associated with ultra-processed foods. As of January 2026, Canadian food sellers will be required to label foods that are high in sodium, sugars and/or saturated fat with a front-of-package nutrition symbol.
“This will help Canadians make better informed choices about the food they eat which helps promote consumption of healthier food,” Health Canada spokesperson André Gagnon told Canadian Affairs in an email.
In Zaltz’ view, public health education should be just one part of the fight to improve Canadian diets.
He says a big part of the solution needs to be making healthy alternatives more readily available.
“Policies to reduce ultra-processed foods in the food supply are best coupled with additional ways to increase consumption of unprocessed or minimally-processed foods, like fruits and vegetables, through a combination of subsidies and increased availability,” he said.
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