You don't, but you provide lower insurance prices to those who can demonstrate a healthy lifestyle. You wouldn't even need too much surveillance to do this. Gi

You don't, but you provide lower insurance prices to those who can demonstrate a healthy lifestyle. You wouldn't even need too much surveillance to do this. Give people a yearly "fitness checkup" to encourage physical exercise, monitor weight to encourage healthy eating habits, do periodic drug tests to discourage drug use etc. If you combined this with a (privacy preserving) fitness band that would monitor your vitals, and only send a list of premiums you're eligible for, you could do even better. You'd have to account for preconditions that make it hard/impossible to exercise, but this would work for most people.