Screen time, other sedentary behaviours, and obesity risk in adults: a review of reviews

Purpose of review: To assess the association between sedentary behaviours, including screen time, and risk of obesity in adults. A review of 10 systematic reviews was undertaken. Recent findings: Available evidence is generally not supportive of associations between sedentary behaviour and obesity in adults. Most studies that found significant associations indicated mostly small effect sizes. Somewhat more consistent associations were shown for screen time (mainly TV viewing), among older adults, and for pre-adult sedentary behaviour to increase the risk of obesity in adulthood. Some evidence also exists for breaks in sedentary time to be associated with a more favourable BMI, and for use of a car to be associated with greater risk of obesity. Summary: There is limited evidence for an association between sedentary behaviour in adulthood and obesity and any association that exists does not seem to be causal. Future research is required investigating potentially positive effects for frequent breaks from sitting, less car use, and an uncoupling of TV viewing and dietary intake