Only in so much as "healthy" might be defined as "lacking observed disease".

Once you use a CGM or have glucose tolerance tests, resting insulin, etc. You'll find levels outside the norm, including inflammation. All indications of Metabolic Syndrome/Disease.

If you can't run a mile, or make it up a couple flights of stairs without exhaustion, I'm not sure that I would consider someone healthy. Including myself.

> Only in so much as "healthy" might be defined as "lacking observed disease".

That is indeed how it's usually evaluated I believe. The sibling comment shows some improvement in this, but also shows that most everywhere this is still the evaluation method.

> If you can't run a mile, or make it up a couple flights of stairs without exhaustion, I'm not sure that I would consider someone healthy. Including myself.

Gets tricky to be fair. Consider someone who's disabled, e.g. can't walk. They won't run no miles, nor make it up any flights of stairs on their own, with or without exhaustion. They might very well be the picture of health otherwise however, so I'd personally put them into that bucket if anywhere. A phrase that comes to mind is "healthy and able-bodied" (so separate terms).

I bring this up because you can be horribly unfit even without being fat. They're distinct dimensions, though they do overlap: to some extent, you can be really quite mobile and fit despite being fat. They do run contrary to each other of course.