I think it's just plus or minus 10 years for whatever fate (genetics) had in store for you. That plus or minus being the little we can control (diet/activity).
So much of the modern US diet that’s being exported to the world negatively impacts life and health span. It’s very much controllable, just harder than the default.
We're also exporting modern US attitudes and psychology (expectations, worldview), which is just an engine for stress. I think overeating is a stress response. Not everyone was a fiend for vanity at the scale we are today.
