I walked into Mary Clearwater’s kitchen as Vancouver’s early morning fog draped itself across the back windows. At 62, Mary had invited me to watch her prepare breakfast—something she’s been doing differently since her cancer diagnosis last year.
“I used to grab whatever was convenient,” she tells me, carefully slicing fresh strawberries onto steel-cut oats. “My pantry was full of things that came in boxes and bags with ingredient lists I couldn’t pronounce.”
Mary is part of a growing community of Canadians reassessing their relationship with ultra-processed foods following a cancer diagnosis. Her personal dietary overhaul now seems validated by emerging research, including a groundbreaking study published in The BMJ last month that suggests consuming ultra-processed foods may increase lung cancer risk—even among people who have never smoked.
The international study followed over 900,000 participants across eight European countries for more than 15 years. Researchers found that for every 10 percent increase in ultra-processed food consumption, there was a 17 percent higher risk of developing lung cancer. This association remained significant even after accounting for smoking status, body mass index, and other established risk factors.
“What surprised many of us was the strength of the association in never-smokers,” explains Dr. Anita Singh, an oncologist at BC Cancer who wasn’t involved in the study but follows nutritional research closely. “This suggests something inherent to these foods might be contributing to cancer development independently of tobacco exposure.”
Ultra-processed foods—defined as industrial formulations containing ingredients rarely used in home cooking—now make up nearly half of many Canadians’ caloric intake according to Statistics Canada data. These include soft drinks, packaged snacks, reconstituted meat products, and many ready-to-eat meals.
Walking through a downtown Vancouver supermarket with nutrition scientist Dr. Regan Hillmer reveals the ubiquity of these products. “The challenge is that ultra-processed foods aren’t just obvious things like chips or frozen pizza,” she points out, examining a seemingly healthy whole-grain bread loaded with additives. “Many products marketed as nutritious contain preservatives, emulsifiers, and other compounds that fundamentally change their properties.”
The mechanisms behind the potential cancer link remain under investigation, but researchers have proposed several pathways. Ultra-processed foods often contain concerning additives like nitrites and nitrates, which can form potentially carcinogenic compounds called nitrosamines during digestion or cooking. Many also come in packaging containing bisphenols and phthalates—known endocrine disruptors with possible carcinogenic effects.
“We’re also increasingly understanding that these foods may disrupt gut microbiome balance,” explains Dr. Hillmer. “A healthy gut microbiome plays a crucial role in immune function and inflammation regulation—both key factors in cancer prevention.”
When I visit the Cedar Community Kitchen in East Vancouver, I find nutrition educator Mai Nguyen teaching a workshop on whole food cooking. The aroma of ginger and garlic fills the room as participants learn to prepare meals emphasizing minimally processed ingredients.
“Many people tell me they don’t have time to cook,” Nguyen says, showing a young mother how to batch-prepare beans for the week. “But once they learn some basic techniques, they realize preparing simple meals can be accessible and affordable.”
For people like Thomas Carroll, 58, who attends these workshops after receiving abnormal results on a recent lung scan, the information feels empowering but also overwhelming. “I grew up in a household where convenience foods were the norm,” he tells me. “Changing those habits isn’t just about information—it’s about confronting cultural patterns and access issues.”
Thomas points to his neighborhood in Surrey, where fresh food markets are scarce but convenience stores abound. His experience highlights what researchers call the “food environment”—the structural factors that influence dietary choices beyond individual willpower.
Health Canada has implemented front-of-package nutrition labeling and restrictions on marketing unhealthy foods to children, but critics argue these measures don’t adequately address the dominance of ultra-processed products in our food system.
“This isn’t just about personal choice,” says Dr. Singh. “We need policies that make minimally processed foods more accessible and affordable while addressing the marketing and availability of ultra-processed alternatives.”
The Canadian Cancer Society now recommends limiting ultra-processed food consumption as part of its cancer prevention guidelines, suggesting Canadians focus on whole or minimally processed foods when possible.
Back in Mary’s kitchen, she acknowledges her privilege in being able to make these changes. “I have time, knowledge, and resources many don’t have,” she says, putting away the morning’s dishes. “But I also think small changes matter. I started by replacing just one processed food at a time.”
As we finish our conversation, Mary shows me a community garden plot she shares with neighbors where they grow vegetables during Vancouver’s mild growing season. “Cancer took so much control away from me,” she reflects, examining a row of emerging kale. “Reconnecting with real food has given some of that back.”
While researchers continue investigating the relationship between diet and cancer risk, studies like the BMJ paper offer Canadians one more reason to reconsider what fills their plates—and potentially, what doesn’t.
