Associations of Mentally Active Versus Passive Sedentary Behavior with Overweight/Obesity in Adults: Role of Patterns and Sex.

: This study assessed associations of total and mental-activity-based sedentary behavior (SB) with the risk of being overweight or obese in adults. The role of sex and SB patterns and the effects of statistically exchanging different mental-activity-based SBs on body mass index (BMI) were explored. : Participants (n = 1154) from the Saudi Post-COVID-19 Sedentary Behavior Survey self-reported demographics, health-related variables, and last-measured body height and weight. BMI was calculated to classify adults as normal weight or overweight/obese. The Sedentary Behavior Questionnaire estimated total and mentally active and passive SB per day, during weekdays, and on weekends. Adjusted logistic regression and isotemporal substitution models assessed the associations of SBs with the risk of being overweight or obese and the effects of displacing mental-activity-based SBs on BMI, respectively. : No significant relationships were observed in the overall sample ( > 0.05). Once sex was considered, the risk of being overweight or obese increased between 5.2% and 10.7% for each hour increase in total and mentally active SBs per day and on weekends in men only ( < 0.05 for all). Replacing one hour of mentally active SB with mentally passive SB resulted in non-significant effects on BMI ( > 0.05). : These findings reveal the importance of distinguishing between SBs based on mental activity for more optimal obesity outcomes, particularly in men. Importantly, exchanging mental-activity-based SBs does not appear to be an effective behavioral strategy to reduce obesity. Obesity prevention and management plans should target reducing total and mentally active SBs daily and on weekends.