Comment by paulpauper

If inactivity were the explanation, it would be possible to fix obesity by having people be more active, yet this this does not work :

https://cdn.vox-cdn.com/thumbor/U1RxtW9oglcck-2g2X_SrKzIA44=...

exercise not help at all. the body compensates in many ways

400 calories burned from a run does not magically offset a donut. The conversion rate may be flat or even negative.

source: https://www.vox.com/2016/4/28/11518804/weight-loss-exercise-...