That's only a problem if healthcare is taxpayer-funded. Otherwise it's your and your insurer's problem to price this in somehow, maybe even offering cheaper plans for people living healthy (e.g. meeting weight goals).
The whole idea behind insurance is that the unlucky ones who require more care than average have their costs covered by those who require less than average. Taxpayer funding systems are literally the same thing.
Yes you can get cheaper premiums by living healthy, but how far do you want to go? Are you going to let your insurance company log everything you eat and how many steps you walk every day? Seems much easier to just factor in the external cost of goods into their price.
The whole idea of insurance is amortization of rare costly events over large numbers of people. Ideally, each person's insurance cost is equal to the expected value of the payout.
When I got my driver's license at age 17 (or possibly the learner's permit? I forget), we learned that the car insurance company would reduce the premium for me if we regularly submitted them some kind of proof that I was getting good grades. It's possible this was some kind of "public-service program to encourage desired behavior", but I suspect that at least part of why they did it was because straight-A students are less likely to get into accidents.
For medical insurance, it seems they could at least do something like "if you send us evidence of healthy exercise/diet/weight, then we'll lower your premiums; otherwise you'll get a premium based on the estimated risk of the set of people who don't do this". (If the government doesn't forbid it. healthcare.gov says "They also can’t take your current health or medical history into account", which sounds like it might rule out some of that.)
2. It was probably also both a community service project AND a reflection of lower expected insurance payout.
3. Maybe the straight-A students are correlated with insurance payers that would rather pay the repair known 1-off payment (or skip doing anything at all) vs the unknown recurring increase in insurance payments?
(Source: drove a dented-up pickup for over a year after a short romp along/into an orchard)
1. What would a tax deduction have to do with an insurer charging lower premiums to its customer?
2. The lower expected payout is exactly what an insurance company is trying to determine, and they’re very good at doing that assuming they have lots of data.
3. Most vehicle insurance cost are liability related, meaning the damage their insured to others, and namely healthcare costs. A collision with another person or their property will not be fixed without the insurance company getting involved, and a reduction in those is what the insurance company is betting on.
