Just record license plates at all fast food restaurants, probably most restaurants, really, average meal runs over 3/4ths of what an average adult male needs to maintain weight.

Liquor stores and bars, too. Ethanol is at least as bad for your body as straight sucrose/fructose.

Log time spent on Facebook, steam, Reddit, etc. Statistically inactivities.

Hell, we could probably reject 75% of Americans in the first three months without any sort of death panels being necessary, just let Google, Target, and walmart machine learn AI the rejection criteria and alert the insurers.