If you want to monitor your own health, here’s some useful factors.
How much are you sleeping and how well
What are you eating
Are you brushing your teeth
Are you getting any exercise
Are you spending time in dangerous environments
(If in China or India) are you spending lots of time in dirty air
Are you spending too much time indoors
You can sleep more, exercise more or differently, eat less or eat differently, have more time in clean air, get outside more
Surely the difference between unhealthy and superhealthy is pretty much all there.
What has Fitbit got to do with any of it?