I’m not too happy with this idea either. I’m still obese, have been for years. I rarely ever go to the doctors. I barely make my Medicare deductible amount each year. When I was still working I had two work partners - both guys on the skinny side. They were both on multiple prescription meds (both on stations, high blood pressure meds, and several others to boot) and both saw doctors probably a dozen times a year or more, vs. my one or two.

Both my sisters are thin and they each see doctors 4-6 times more often than I do. My thinnest sister, with a borderline underweight BMI, sees doctors about 1-2 times a month on average, constantly going for checkups for this or that.

If you’re going to tax people then apply a tax to people who overuse the system, not just based on some arbitrary physical condition.