Those who are already reasonably fit, will see the lock down as an opportunity to eat a healthier diet with less flour, more complex carbs, and more vegetables. They know where dey gettin' dat from. These folk will find a way to do more walking or running up and down stairs indoors, or same in their li'le gyarden.

I don't expect ppl who live a fit lifestyle to get dat much fatter. Basically people will be expected to do more of what dey already did. The fit will do more fitness and proper dieting - whilst the already fat will gorge more on carbs and be couch-potatoes.
I'm open to arguments! Bring it on!