I think these long term health outcomes are one of the best arguments for single payer insurance. We know obesity drives up the costs of healthcare. We know that managing obesity will bring down total healthcare costs and long-term insurance payouts. But insurance companies don’t want to pay in the short term for something that benefits in the long term, because people change insurance plans when they change jobs. So they are logically opposed to paying now when it’s the next insurance company that benefits.
This is a case where more regulation will make the market more efficient. The efficiency of insurance, in particular, benefits when the pool of customers is as large as possible.