Obesity in Canada surges to one-third of adults, study links spike to pandemic disruptions

Obesity rates in Canada have reached alarming levels, with one in three adults now classified as obese, according to a new study published in the Canadian Medical Association Journal (CMAJ). Researchers say the COVID-19 pandemic played a major role in accelerating this trend.

The study shows that 32.7 percent of Canadian adults, roughly 10.6 million people, were obese in 2023. That’s a jump of eight percentage points since 2009, with a sharper rise during the pandemic years.

“The pandemic had such a profound impact on our daily lives, including changes in our eating behaviours and access to healthy foods,” said Laura Anderson, lead author of the study and associate professor at McMaster University.


The research analyzed self-reported body mass index (BMI) data from 746,250 Canadians aged 18 or older between 2009 and 2023. Obesity was defined using World Health Organization criteria as a BMI of 30 or higher, or 27.5 for Asian populations.

Before COVID-19, obesity rates in Canada were rising at about 0.5 percentage points per year. During the pandemic, that rate doubled to 1 percent annually. While the study didn’t investigate causes directly, experts suggest that mental health and lifestyle disruptions contributed significantly.

“There was isolation and depression,” said Dr. Sean Wharton, an internal medicine physician in Ontario. “People who were living with depression, their depression may have gotten even worse. And that’s where we saw people having an increase in their weight.”

The study also found that young adults aged 18 to 39 experienced the highest increases. Severe obesity, defined as a BMI of 40 or more, rose from 2.4 percent in 2009 to nearly 5 percent in 2023. More women were also affected by severe obesity, which researchers say may reflect increased stress and caregiving responsibilities during the pandemic.

While new weight-loss drugs like Wegovy have been approved in Canada, they were not widely available during the study period. Their long-term impact on national obesity rates remains to be seen.

Researchers say the rise in severe obesity is especially concerning due to its links to chronic diseases like diabetes, heart disease, and certain cancers.