For a country that is so weighed down by the health issues around obesity, it's quite weird taxes/incentives based on calorie per gram isn't anywhere in sight. The savings from not having to take care of so much sick people would be enormous.

It's clear from the situation that the free market choices are suboptimal. Who wants to suffer through most of their life and die early? Yet these choices are still made. If you can't educate, then tax fairly and force them to make the right choices.