"Couch-potatoeism" and childhood obesity: The inverse causality hypothesis.

The bulk of cross-sectional studies suggests that lower levels of physical activity are associated with childhood obesity. Although this has led to the general understanding that "couch-potatoes" are fat on account of their inactive lifestyles, cross-sectional studies do not imply causality. On the contrary, the contribution of physical activity to obesity during childhood is currently unclear, and lately, studies have suggested that "couch-potatoeism" could be the result of obesity rather than its cause. Coupled with evidence suggesting that interventions have had little effect on children's physical activity levels as well as on obesity, this inverse causality challenges the role of physical activity in childhood obesity prevention strategies.