Body Weight Changes and their Determinants During the COVID-19 Pandemic: A Systematic Review

BACKGROUND: The COVID-19 pandemic has been recognized as a significant public health concern. This systematic review examines the effects of the COVID-19 pandemic on weight changes and their determinants, particularly within the contexts of physical activity and nutrition. MATERIALS AND METHODS: Literature search was conducted using the Google Scholar, MEDLINE, PSYCHINFO, and SCIENCE DIRECT databases (2020-2021). Search terms included obesity, weight changes, body mass index (BMI), diet, physical activity, weight-related behaviors, pandemic, lockdown, coronavirus, and COVID-19. The search was limited to articles published in English. RESULTS: A total of 35 studies were included in this review. The majority of the studies were cross-sectional in design and employed online, self-reported sampling methods. Weight gain was reported in most of individuals (19.5-50.0%), although some studies documented weight loss (13.8-50.7%). An increase in food consumption was observed among 39-65% of participants. A greater proportion adhered to healthy dietary patterns (6.1-41%) compared to unhealthy diets (26.7-50.0%). Conversely, a decline in physical activity levels was reported (6.5-69.0%). Sedentary behaviors increased, with screen time and sitting time rising (36.2-74.4% and 54.4-63.0%, respectively). CONCLUSION: The COVID-19 pandemic has been associated with increased weight gain, largely attributable to lifestyle changes, including dietary habits and reduced physical activity. Individual characteristics and pre-pandemic lifestyle factors appear to be predictive of weight-related outcomes during the pandemic. Healthcare professionals should consider individual differences, psychological coping mechanisms, and socioeconomic factors when designing effective weight management programs during a public health crisis.