Actually we didn't need to wait for Covid - it's already been known for decades that obesity's a factor in poor outomes from many ailments
Indeed, 90% increase risk from COVID at 40 BMI, is lower than the increased risk of a stroke from many studies (this added risk thing is difficult as it's so difficult to control for unknowns, but that applies to COVID as much as other things, especially as obesity goes in hand with other things.)
However if an additional fear of covid helps you lose the weight, then that's good full stop, how to lose the weight is the problem people have, I'm sure everyone knows (on some level) the risk their weight brings.