It’s not exactly news that junk food isn’t healthy.
What may be surprising is exactly how pervasive ultra-processed foods (UPFs) have become and what harm they’re doing. This includes some foods that are specifically labelled and marketed as having nutritional value.
We are nutrition researchers, and the authors of a new study that identifies some of the specific negative effects of ultra-processed foods that are readily available, very popular and often hard to resist, especially when people are feeling pressed for time.
Our research group leads population-based studies that integrate nutrition epidemiology, food policy, and dietary assessment to better understand how modern food environments and dietary patterns influence chronic disease risk.
While ultra-processed foods include obvious culprits like potato chips, candy and frozen pizza, there are also some that people may believe are good for them, such as packaged granola bars, sports drinks and fruit-filled yogurt. Our study used the Nova classification system to define UPFs, which are industrial formulations made mostly or entirely from substances extracted from foods, derived from food constituents with little if any intact whole food remaining.
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How UPFs harm health
Our research, based on diet questionnaires and personal medical data that Health Canada and Statistics Canada collected from over 6,000 Canadians, shows that the effects of UPFs can pile up over time, adding to the risk of heart attack, stroke and other serious health issues by raising blood pressure and blood sugar levels, for example.
Even a person who is thin, active and free from illness might be accumulating risk by consuming UPFs that may seem innocuous or even healthy.
The ways ultra-processed foods harm our health aren’t just about calories or individual nutrients like salt, sugar and fat, though those aren’t making things better. It’s also in the way they’re made.
Take that seemingly healthy tub of yogurt. On its own, yogurt is indeed very healthy. The problem is when things like jam-like fruit with preservatives or artificial vanilla flavouring are added. They make yogurt taste better but can push it into unhealthy territory.
Even after we eliminated the impacts of influences such as the survey respondents’ body mass index, age, exercise and smoking habits, the numbers showed a specific risk that may be related to the additives that give ultra-processed foods longer shelf life, brighter colours and enhanced flavours. For example, we know that the modern diet of highly processed food is associated with distorted hormone levels.
Some products are so heavily processed that it appears our bodies may not respond to them as they would to more natural foods. UPFs trigger inflammatory responses that suggest the body regards them as stressors, rather than nutrition.
Substituting UPFs for healthy foods
We learned from survey respondents that consumers are increasingly using UPFs as substitutes for healthy staples such as vegetables and fruit. This is not surprising when the wrapper on a granola bar proclaims its contents to be a good source of fibre, or a when a sports drink label says it’s a good source of electrolytes, Vitamin D or some other single nutrient.
While these claims are factual, they don’t represent the entire or even most significant effects of the products inside. For a long time, food policies have been very focused on single nutrients rather than thinking about the totality of our food supply.
Our complex food supply has come to be heavily influenced by huge multinational companies and their need for sales instead of our need for health, to the point where marketing and packaging have made it challenging to understand exactly what we are eating or drinking.
That is starting to change. Starting in January 2026, the Canadian government will require food packaging to prominently declare the presence of unhealthy amounts of sodium, sugar and saturated fat.
Read more: Front-of-package food labels: A path to healthier choices
While that will be a significant and welcome improvement in transparency, it will not change the fact that a loaf of mass-manufactured white bread, a package of bacon or even a tray of muffins may also be harming the people who eat them in ways they have not even considered.
Setting reduction targets
Canada’s food guide, produced by Health Canada, only suggests we limit the amount of processed food we eat, but it doesn’t set any clear national target for how much we should cut our consumption. While most other countries also stop short of setting specific limits, France has gone a step further by aiming to cut national consumption of ultra-processed foods by 20 per cent over five years.
Setting a similar national reduction target in Canada could have a particularly significant, positive effect on people in care homes, hospitals and schools that are required to use Canada’s Food Guide in planning their menus.
Individual consumers know how easy it is to fall into the habit of eating too many ultra-processed foods. They are hard to resist because they are heavily marketed, usually tasty, reasonably affordable and appear to make life easier by saving time and effort.
Understanding more about what these appealing products are really doing to people is an important step toward helping consumers make better, more informed choices. We are already working on more research to understand more about what’s really inside those bright shiny packages that keep finding their way into shopping carts.
