Researchers at the University of Toronto are sounding the alarm about high consumption of ultra-processed foods among preschool-aged children in Canada - and its association with obesity development.
In a study published in JAMA Network Open , the researchers compared data from food frequency questionnaires completed when children were three years old with physical measurements taken at age five, including BMI (body mass index), waist-to-height ratio, waist circumference and skinfold thickness.
They found a link between higher consumption of ultra-processed foods at age three and increased risk of overweight or obesity and higher body fat measurements at age five.
"We saw that ultra-processed foods contributed to almost half of a child's total daily energy intake," says Kozeta Miliku, assistant professor of nutritional sciences at U of T's Temerty Faculty of Medicine and senior author of the study.
The associations were primarily seen in males and remained significant after accounting for other factors such as parent education and whether the child was breastfed. These findings are the first to describe sex-driven differences in the effects of ultra-processed food on obesity risk among Canadian children.
Ultra-processed foods are those that have been industrially produced and contain ingredients not typically found in a home kitchen, like emulsifiers, preservatives and artificial colours and flavours. The broad category includes items like soda, instant noodles and chips, as well as less obvious foods like flavoured yogurts and commercially prepared whole-grain breads.
The researchers utilized data from over 2,200 children enrolled in the CHILD Cohort Study , one of the largest prospective pregnancy cohort studies in Canada, which collects information from families starting in pregnancy and at key developmental stages to track the impact of genetic and environmental factors on children's long-term health.
In ongoing follow-up studies, the researchers are looking at whether replacing some of the ultra-processed foods with minimally processed whole foods can help reduce the negative effects on body composition and obesity risk. They are also trying to understand why males seem to be especially vulnerable to the health harms related to ultra-processed foods and what role the gut microbiome might play in these adverse health outcomes.
Miliku notes that early childhood is a critical developmental window because food preferences and habits established during this time can carry into adulthood.
But as a mom to a three-year-old who can't completely avoid ultra-processed foods, she also understands first-hand the challenges parents face in trying to feed their child a well-balanced diet. "Ultra-processed foods are very accessible and a handy solution for busy days. We are all doing our best to make sure our children are fed, but there are opportunities for us to improve their diet," Miliku said.
"Ultra-processed foods are common in today's retail market, but they are not all easy to spot," says Zheng Hao Chen, a PhD student in Miliku's lab and lead author of the study, who adds Canada is among the top consumers of ultra-processed foods worldwide.
The researchers point to the Nutri-Score label used in France - a colour-coded scale ranging from A to E - and food-specific taxes as measures that have worked in other countries to encourage people to eat less ultra-processed foods.
Miliku also acknowledges that with an increasing number of Canadian households experiencing food insecurity, broader policy supports are needed to ensure the affordability and accessibility of fresh whole foods.
"Canada is falling behind in this area. With overweight and obesity affecting nearly one in three children in this country, it's scary that we are not taking more action," Miliku says.
She hopes that the study will spur regulators to adopt public health policies, like front-of-package nutrition labelling, to make it easier for families to choose healthier, less processed options.
The study was funded by a University of Toronto Temerty Faculty of Medicine Pathway Grant. The CHILD Cohort Study is funded by Allergy, Genes and Environment Network of Centres of Excellence, Canadian Institutes of Health Research and Genome Canada.
