Ultra-Processed Foods: Truths, Myths and the New Brain Health Research, According to a Registered Dietitian

By Hannah Malayko, Registered Dietitian - NutriProCan Dietitians

Ultra-processed foods (UPFs) aren't poison, but eating a lot of them is linked to poorer health. A new Canadian study published in October 2026 found that adults who ate the most ultra-processed food were 40% more likely to show silent signs of brain injury on MRI. You don't need to eliminate packaged foods. The goal is to build most of your meals around whole and minimally processed foods, and use convenience foods strategically.

Key takeaways

• Ultra-processed foods are industrially made products with ingredients you wouldn't use at home, such as emulsifiers, flavour enhancers and colourings.
• A 2026 study of 8,783 Canadians aged 35 to 69 linked the highest UPF intake to more silent brain damage and more belly fat.
• The study shows an association, not proof that UPFs cause brain damage.
• Not all UPFs are equal: a fortified whole grain cereal and a can of pop are nutritionally very different.
• Your overall eating pattern matters far more than any single food.

If you've spent any time on social media lately, you've probably seen alarming headlines calling ultra-processed foods "poison" or "addictive." At the same time, many people rely on packaged foods to get meals on the table while juggling work, family and other responsibilities.

As a Registered Dietitian, one question I hear more and more is: "Should I stop eating ultra-processed foods?" The answer isn't a simple yes or no. Let's look at what ultra-processed foods are, what the latest research says, and how to make practical choices in today's busy world.

What are ultra-processed foods?

Ultra-processed foods are foods that go through multiple industrial processing steps and contain ingredients not typically used in home cooking, such as emulsifiers, flavour enhancers, preservatives, colourings and stabilizers.

Researchers sort foods using the NOVA food classification system, which groups foods by how much and why they are processed:

NOVA group	What it means	Examples
1. Unprocessed or minimally processed	Whole foods, lightly altered	Fresh or frozen fruits and vegetables, plain yogurt, eggs, milk, oats, dried beans
2. Processed culinary ingredients	Used to cook and season	Olive oil, butter, sugar, salt
3. Processed foods	Whole foods with a few added ingredients	Cheese, canned vegetables, canned beans, canned tuna, simple breads
4. Ultra-processed foods	Industrial formulations with additives	Soft drinks, candy, packaged pastries, chips, instant noodles, many frozen meals, processed meats, sugary breakfast cereals

NOVA is the most widely used system in research, but it classifies foods by processing, not by nutrient content or health impact. That's an important limitation we'll come back to.

Is all processed food bad for you?

No. Almost all food is processed to some degree, and processing often helps. It can improve food safety, extend shelf life, reduce food waste and make nutritious foods more convenient.

• Frozen vegetables are processed but keep most of their nutritional value.
• Plain Greek yogurt is processed but provides high-quality protein and calcium.
• Canned beans offer fibre, plant protein and important minerals.
• Pasteurized milk is processed to make it safe to drink.

Processing itself isn't the problem. The nutritional quality of the finished product is what matters.

New 2026 Canadian study: ultra-processed foods and brain health

In October 2026, researchers at the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences published a study in JAMA Network Open that made national headlines.

What they studied: The team looked at 8,783 Canadians aged 35 to 69 with no history of heart disease. Participants came from two long-running Canadian studies, the Canadian Alliance for Healthy Hearts and Minds and PURE-MIND. Each person completed a detailed food questionnaire and had an MRI brain scan. Neurologists reading the scans did not know what anyone ate.

What they found:

• On average, ultra-processed foods made up about 25% of participants' daily food servings. The heaviest consumers got 45% of their servings from UPFs, compared with 16% for the lightest.
• People in the highest-intake group were 40% more likely to show silent vascular brain injury, such as tiny "silent strokes" and damage to the brain's white matter. These changes cause no obvious symptoms but are considered early warning signs for stroke and memory problems later in life.
• The link was stronger in women. Women with the highest intake were nearly twice as likely to show these changes as women with the lowest intake.
• High UPF eaters also carried more body fat and more deep belly fat, a type of fat linked to inflammation and blood vessel damage.
• UPFs crowded out whole foods. Whole and minimally processed foods made up 68% of servings in the lowest-UPF group but only 41% in the highest. As lead author Russell de Souza put it, "these foods appeared to crowd out healthier whole foods."
• The study did not find a link with scores on brief thinking and memory tests.

What it doesn't tell us: Participants were assessed only once, so the study can't prove that ultra-processed foods cause brain damage. The researchers say longer-term studies with repeated MRI scans are underway to see whether cutting back can slow or prevent these changes.

My take as a dietitian: This is a well-designed Canadian study, and it adds to the evidence that what we eat in our 30s to 60s shapes brain health later on. A "40% higher likelihood" is a relative number, though. It describes the heaviest eaters compared with the lightest, not the effect of one bag of chips. The practical message hasn't changed: make whole foods the foundation of your plate, and the brain, heart and waistline all benefit.

What else does the research say about ultra-processed foods?

Large observational studies have linked diets high in ultra-processed foods with a higher risk of:

• Cardiovascular disease and stroke
• Type 2 diabetes
• Obesity
• Some cancers
• Depression
• Earlier death

Association is not causation. People who eat the most UPFs often differ in other ways too. They may eat fewer fruits and vegetables, get less fibre, exercise less, have higher stress or have limited access to fresh food. Still, UPFs generally offer less nutrition than their whole-food equivalents. It makes sense to favour whole foods while allowing flexibility for processed foods that are hard to avoid.

Are all ultra-processed foods equally unhealthy?

No. One limitation of NOVA is that it groups foods with very different nutritional profiles. All of these can count as ultra-processed:

• Flavoured high-protein Greek yogurt
• Packaged whole grain sandwich bread
• Whole grain breakfast cereal fortified with iron
• Fortified unsweetened soy beverage
• Protein bars
• Plant-based meat alternatives
• Soft drinks
• Candy
• Packaged cookies

These foods clearly don't contribute equally to our health. As dietitians, we look beyond processing to the whole nutritional picture:

• Fibre and protein
• Added sugars, sodium and saturated fat
• Vitamins and minerals
• Portion size and how often the food is eaten
• How it fits into your overall eating pattern

Is it OK to rely on convenience foods?

Yes. Convenience isn't something to apologize for. For busy parents, shift workers, students, caregivers and older adults, convenient foods can make healthy eating more realistic. Here are smart options and how to boost them:

Convenience food	Dietitian tip
Bagged salad mixes	Go light on the dressing
Frozen vegetables	Choose plain or low-sodium options
Rotisserie chicken	Remove the skin to cut saturated fat
Whole grain wraps	Fill with vegetables and lean protein
Canned tuna or salmon	Choose packed in water rather than oil
Microwavable brown rice	Pair with frozen vegetables for a fast bowl
Individual Greek yogurts	Choose plain; add fruit, nuts or a drizzle of honey
Frozen fruit	Add to oats, yogurt or smoothies
Pre-cut vegetables	Keep at eye level in the fridge for snacking

Nutrition doesn't have to mean hours in the kitchen.

What eating pattern is best for long-term health?

Research consistently links better long-term health, including brain health, with eating patterns rich in:

• Vegetables and fruit
• Whole grains
• Legumes
• Nuts and seeds
• Healthy fats (avocado, olive oil, nuts and seeds)
• Fish
• Lean proteins (chicken breast, extra-lean ground beef, tofu, eggs, lower-fat dairy)

Enjoying packaged foods occasionally, or even regularly, doesn't automatically make your diet unhealthy. It's the balance over time that matters.

5 practical tips for eating well in an ultra-processed world

1. Build your plate around whole foods. Aim for vegetables or fruit, a whole grain and a protein at most meals. In the PHRI study, the lowest-UPF eaters got about two-thirds of their servings from whole foods. That's a useful target.
2. Read the Nutrition Facts table, not just the ingredient list. Use the % Daily Value: 5% or less is a little, 15% or more is a lot. Look for more fibre and protein, and less added sugar, sodium and saturated fat.
3. Pair, don't replace. Add frozen vegetables to boxed pasta, hummus to crackers, berries and nuts to yogurt, or a big salad to frozen pizza.
4. Swap one food at a time. Try one swap a week, like sugary cereal for a fortified whole grain option or pop for sparkling water.
5. Batch-prep on calmer days. Cook a pot of grains, beans or roasted vegetables so whole-food options are ready on busy nights.

And remember: perfection isn't the goal. Food is about nourishment, enjoyment, culture, convenience and connection. Trying to eliminate every ultra-processed food creates unnecessary stress and isn't realistic for most people. Watch your pattern over a week rather than judging a single meal.

The bottom line

Ultra-processed foods have become an easy target in nutrition conversations, but the reality is nuanced. New Canadian research adds a real reason to pay attention, especially for brain health in midlife. It doesn't mean every packaged food is harmful.

Some UPFs offer little nutrition and are best enjoyed less often. Others provide important nutrients, save time and reduce food waste. Rather than fearing processing, focus on a balanced pattern built mostly on whole foods. Small, sustainable changes will always beat chasing the latest nutrition trend.

Feeling overwhelmed by conflicting nutrition advice? Book a session with Hannah Malayko, RD, at NutriProCan Dietitians for personalized, evidence-based guidance that fits your life. Click here

FAQ

Do ultra-processed foods cause dementia? Research hasn't proven that. A 2026 Canadian study in JAMA Network Open found adults eating the most ultra-processed food were 40% more likely to show silent brain injury on MRI, an early warning sign for stroke and memory problems. Because it measured people once, it shows a link, not cause.

What is a "silent stroke"? A silent stroke is a small area of brain damage from reduced blood flow that causes no obvious symptoms. It is usually found by chance on an MRI and raises the risk of future stroke and memory decline.

How much ultra-processed food is too much? There's no official cut-off. In the 2026 PHRI study, the highest-risk group got about 45% of daily food servings from ultra-processed foods, while the lowest got about 16%. Aim to make whole and minimally processed foods the majority of what you eat.

What foods are ultra-processed? Common examples are soft drinks, candy, chips, packaged pastries and cookies, instant noodles, sugary breakfast cereals, processed meats like hot dogs and deli meats, and many ready-to-heat frozen meals.

Are frozen vegetables and canned beans ultra-processed? No. Plain frozen vegetables are minimally processed, and canned beans are a "processed" food in the NOVA system, not ultra-processed. Both are nutritious, affordable staples.

Can some ultra-processed foods be healthy? Yes. Fortified whole grain cereals, packaged whole grain bread, fortified soy beverages and some protein-rich yogurts are technically ultra-processed but can fit well in a balanced diet. Check fibre, protein, added sugar and sodium on the Nutrition Facts table.

What is the NOVA food classification system? NOVA is a research system that sorts foods into four groups by how much they are processed: unprocessed or minimally processed foods, processed culinary ingredients, processed foods and ultra-processed foods. It does not rate nutritional value.