Background The COVID-19 pandemic and related lockdowns have impacted lifestyle behaviors, including eating habits and physical activity; yet, few studies have identified the emerging patterns of such changes and associated risk factors. Objective This study aims to identify the patterns of weight and lifestyle behavior changes, and the potential risk factors, resulting from the pandemic in Canadian adults. Methods Analyses were conducted on 1609 adults (18-89 years old; n=1450, 90.1%, women; n=1316, 81.8%, White) of the Canadian COVIDiet study baseline data (May-December 2020). Self-reported current and prepandemic weight, physical activity, smoking status, perceived eating habits, alcohol intake, and sleep quality were collected through online questionnaires. Based on these 6 indicator variables, latent class analysis (LCA) was used to identify lifestyle behavior change patterns. Associations with potential risk factors, including age, gender, ethnicity, education, income, chronic diseases, body image perception, and changes in the stress level, living situation, and work arrangement, were examined with logistic regressions. Results Participants’ mean BMI was 26.1 (SD 6.3) kg/m2. Of the 1609 participants, 980 (60.9%) had a bachelor’s degree or above. Since the pandemic, 563 (35%) had decreased income and 788 (49%) changed their work arrangement. Most participants reported unchanged weight, sleep quality, physical activity level, and smoking and alcohol consumption, yet 708 (44%) reported a perceived decrease in eating habit quality. From LCA, 2 classes of lifestyle behavior change emerged: healthy and less healthy (probability: 0.605 and 0.395, respectively; Bayesian information criterion [BIC]=15574, entropy=4.8). The healthy lifestyle behavior change group more frequently reported unchanged weight, sleep quality, smoking and alcohol intake, unchanged/improved eating habits, and increased physical activity. The less healthy lifestyle behavior change group reported significant weight gain, deteriorated eating habits and sleep quality, unchanged/increased alcohol intake and smoking, and decreased physical activity. Among risk factors, body image dissatisfaction (odds ratio [OR] 8.8, 95% CI 5.3-14.7), depression (OR 1.8, 95% CI 1.3-2.5), increased stress level (OR 3.4, 95% CI 2.0-5.8), and gender minority identity (OR 5.5, 95% CI 1.3-22.3) were associated with adopting less healthy behaviors in adjusted models. Conclusions The COVID-19 pandemic has appeared to have influenced lifestyle behaviors unfavorably in some but favorably in others. Body image perception, change in stress level, and gender identity are factors associated with behavior change patterns; whether these will sustain over time remains to be studied. Findings provide insights into developing strategies for supporting adults with poorer mental well-being in the postpandemic context and promoting healthful behaviors during future disease outbreaks. Trial Registration ClinicalTrials.gov NCT04407533; https://clinicaltrials.gov/ct2/show/NCT04407533

BACKGROUND The COVID-19 pandemic and related lockdowns has impacted lifestyle behaviours including eating habits and physical activity; yet few studies identified emerging patterns of such changes and associated risk factors. OBJECTIVE The objective was to identify patterns of weight and lifestyle behaviour change, and potential risk factors, resulting from the pandemic in Canadian adults. METHODS Analyses were conducted on 1,609 adults (18-89 y; 90.1% women; 81.8% White) of the Canadian COVIDiet study baseline data (May-Dec 2020). Self-reported current and pre-pandemic weight, physical activity, smoking status, perceived eating habits, alcohol intake and sleep quality were collected by online questionnaires. Based on these 6 indicator variables, latent class analysis (LCA) was used to identify lifestyle behaviour change patterns. Associations with potential risk factors including age, gender, ethnicity, education, income, chronic diseases, body image perception, and changes in stress level, living situation and work arrangement were examined with logistic regressions. RESULTS From LCA, 2 classes of lifestyle behaviour change emerged; “healthy” and “less healthy” (probability: 0.605 and 0.395; BIC=15574.3, entropy=4.8). “Healthy” class participants more frequently reported unchanged weight, sleep quality, smoking and alcohol intake, unchanged/improved eating habits and increased physical activity. The “less healthy” class reported significant weight gain, deteriorated eating habits and sleep quality, unchanged/increased alcohol intake and smoking, and decreased physical activity. Among risk factors, body image dissatisfaction [OR=8.8, 95%CI(5.3-14.7)], depression [OR=1.8, 95%CI(1.3, 2.5)], increased stress level [OR=3.4, 95%CI(2.0, 5.8)] and of gender minority identity [OR=5.5, 95% CI (1.3-22.3)] were associated with adopting “less healthy” behaviours in adjusted models. CONCLUSIONS The COVID-19 pandemic appeared to have influenced lifestyle behaviours unfavorably in some, but favorably in others. Body image perception and change in stress level may have modulated these changes; whether these will sustain overtime remains to be studied. CLINICALTRIAL ClinicalTrials.gov Identifier: NCT04407533