I agree everyone should eat a healthy diet and exercise regularly, but that is impossible to verify.
How would the government (or a private insurer for that matter) attempt to verify whether I ate Kashi cereal for breakfast instead of an egg mcmuffin and coke at the nearest mcd's drive-thru? Random blood draws and expensive blood analysis?
How would the government attempt to verify whether I exercised getting my heart rate above 120 for 20 minutes at least 4 times a week? Mandatory wifi-enabled heart-rate monitors for everyone, to be worn 24/7?
In either case, there would be massive fraud, and efforts to combat fraud would lead to wholesale violation of personal privacy in contravention of established 4th amendment constitutional law.
One could start with a few well known food items and move from there I suppose.
I.e. milk goes from 4% fat --> 0% fat (skim).
For meat, there are well known measures of how lean the meat is.
For bread, the more grains it has makes it more healthy (I think).
You would only be able to tax the extremes though. For different people, different amount fat, etc... are correct depending on their body types, exercise habits, family history, etc...
For eating... your right, I can't think of a good system.
For exercise, some insurance companies give benefits for going to a gym some number of times a week/month/year. Its not perfect, but I would suspect it probably has few false positives.
How would the government (or a private insurer for that matter) attempt to verify whether I ate Kashi cereal for breakfast instead of an egg mcmuffin and coke at the nearest mcd's drive-thru? Random blood draws and expensive blood analysis?
How would the government attempt to verify whether I exercised getting my heart rate above 120 for 20 minutes at least 4 times a week? Mandatory wifi-enabled heart-rate monitors for everyone, to be worn 24/7?
In either case, there would be massive fraud, and efforts to combat fraud would lead to wholesale violation of personal privacy in contravention of established 4th amendment constitutional law.