Well, no, not really. I mean we all want simple solutions that require us to do as little as possible but… turns out that’s not biologically feasible.
As we age our bone density decreases and so does our muscle mass. That leads to aches and injuries. Consuming more calcium and protein won’t help on its own; what is required is weight-bearing exercises. These stress the bones, resulting in the release of calcitonin, which increases calcium uptake and helps maintain bone density. Likewise weight-bearing exercise helps prevent muscle loss through the same type of feedback mechanism. Studies have shown this phenomenon quite consistently (for examples of such studies take a look at the work of Simon Melov at the Buck Institute for Age Research). Walking, gardening, etc. while pleasant activities will most definitely not help bone density and muscle retention. Thus you will suffer stress-related injuries more often as you age. And that’s a poor outcome.
In addition the so-called “Blue Zones” studies fail to account for the fact that populations are not heterogenous across the planet; genetic factors come into play as well as environmental factors. Thus there may be genetic reasons why people in some places have slightly better health outcomes than in others, as well as environmental reasons.
So yes, we really ought to be a lot more active than we are. But canceling your gym membership (assuming you even turn up after you’ve paid your annual dues during that post-holiday-season period of remorse…) is a really bad idea.