COVID-19 Pandemic Accelerates Obesity Rates in Canada: Study Insights

A recent study published in the Canadian Medical Association Journal (CMAJ) reveals a significant increase in obesity rates among Canadians, particularly during the COVID-19 pandemic. The research indicates that approximately one-third of Canadians, or 32.7%, are now classified as obese, marking an eight percentage point rise since 2009. This alarming trend is particularly pronounced among young adults and women, suggesting profound changes in lifestyle and health behaviors triggered by the pandemic.

According to Dr. Laura Anderson, lead author of the study and Associate Professor at McMaster University, the pandemic significantly altered daily routines, impacting dietary habits and access to healthy food options. “The pandemic had such a profound impact on our daily lives,” Anderson stated in the July 14, 2025 report. The study analyzed self-reported body mass index (BMI) data from 746,250 Canadians aged 18 and older, collected from 2009 to 2023.

The World Health Organization defines obesity as having a BMI of 30 or higher, a metric that, despite its limitations, remains a standard for population-level health assessments. Prior to the pandemic, Canada saw a gradual annual increase in obesity rates of approximately 0.5 percentage points. However, during the pandemic, this rate doubled to about one percentage point per year.

Dr. Sean Wharton, an internal medicine specialist and Medical Director at Wharton Medical Clinic, highlights the mental health implications of the pandemic. “There was isolation and depression,” he noted, emphasizing that individuals suffering from mental health issues were likely to experience weight gain. Wharton, who did not participate in the study, expressed skepticism about future declines in obesity rates, arguing that once weight is gained, it is challenging to lose.

The data also reveals a concerning trend among women and young adults. During the pandemic, the obesity rate among young adults aged 18-39 saw the steepest increase, with women particularly affected by severe obesity, defined as a BMI of 40 or higher. Anderson posits that increased caregiving responsibilities and stress may have contributed to this rise.

Angela Martin, a nurse from Toronto who experienced significant weight gain during the pandemic, recounts her struggle with obesity exacerbated by the closure of gyms and exercise classes. “Looking back, I was so not fine,” she reflected, highlighting the psychological and social challenges faced during this period.

The rise in obesity rates raises concerns about associated health complications, as Dr. Wharton noted, with increased risks for conditions such as Type 2 diabetes, heart disease, and certain cancers. The study found that while half of those classified as obese did not have chronic health conditions, a notable percentage suffered from multiple long-term health issues.

Interestingly, the study does not account for the potential effects of new weight-loss medications, such as Wegovy, which became more accessible post-pandemic. Future research may reveal how these treatments influence obesity trends in Canada.

As Canadian health officials and researchers grapple with these findings, the need for comprehensive strategies to address obesity and related health implications has never been more urgent. The long-term effects of the pandemic on public health are still unfolding, necessitating ongoing monitoring and intervention to mitigate the growing obesity crisis in Canada.