Obesity rates surged in Canada during COVID-19 pandemic, study finds

A new study has found a rapid rise in obesity rates primarily among young adults and women in Canada. John Vennavally-Rao on the factors behind the increase.

A new Canadian study found the country’s already rising obesity rates accelerated during the COVID-19 pandemic, with experts pointing to major lifestyle disruptions as a likely factor.

Led by researchers at McMaster University, the study analyzed 15 years of data from nearly 750,000 Canadian adults. It found the rate of obesity rose much faster during the pandemic than it had in the preceding decade.

Using body mass index (BMI) to gauge obesity levels, the study found the national obesity rate rose from 25 per cent in 2009 to 33 per cent by 2023. During the pandemic years, the rate of increase doubled, with obesity rates climbing by nearly a full percentage point annually.

“It’s quite concerning, because having obesity has all kinds of health implications for society and for the individuals involved,” said Arthur Sweetman, co-author of the study.

Obesity can increase the risk of serious health conditions such as Type 2 diabetes and certain cancers.

“Clearly, there were lockdowns during the pandemic. People were less physically active. Gyms were closed,” Sweetman said. “It’s possible that people working remotely weren’t eating as well.”

Sweetman also said the rate of obesity rose at a much higher rate for women and young people, suggesting they may have been more affected by isolation and the broader pressures of the pandemic.

The researchers now want to know whether this was a temporary spike or a permanent shift.

“We not only need to know why obesity rates went up, but also if it’s begun to slow back to what it used to be,” he said.

Sweetman also acknowledged that the study data ended before the widespread adoption of new anti-obesity medications like Wegovy, which may have already started to bend the curve.

He also noted the rate of increase in severe obesity, typically defined as a BMI of 40 or higher, rose even faster than the overall obesity rate.

While the researchers acknowledge BMI is an imperfect tool for assessing obesity in individuals, they maintain that it remains useful for identifying trends at the population level.

Dr. Sean Wharton, an obesity expert who was not involved in the study, says we don’t really know why obesity rates accelerated, but agrees some did turn to high-calorie comfort food at the time.

“It was a comfort and we needed it. We needed the food, the carbohydrates,” said Wharton. “We know that it increases weight. But it also makes us feel a lot better. So I think that was probably part of it.”

Wharton says isolation and depression through the pandemic may have led to “greater amounts of calories going in.”

Obesity Canada emphasizes that the issue is far more complex than overeating.

With obesity now recognized as a chronic disease, the organization stresses it is not solely about personal choices, but influenced by societal factors, stress, and genetics, adding that women, especially caregivers, may have been disproportionately affected.

“Women did shoulder a lot of the burden during the pandemic and they’re responsible often for what that home looks like and what food looks like,” said Obesity Canada Executive Director Lisa Schaffer.

“It’s upsetting and it’s distressing,” she added. “It kind of confirms what we’ve known all along, that people with untreated chronic diseases are going to have a harder time when the health care system and life in general gets that challenging.”

The study also found a small increase in the number of Canadians classified as underweight during the pandemic.

“Being underweight is also a fairly serious potential health problem, so we need to be watching both ends of the BMI spectrum,” Sweetman said.