I think the Federal government can require reasonable warning labels and signage, but it cannot constitutionally punish somebody for using a legal product. The government can legitimately make information available so long as the source of that information is also made available--fat content, trans fats, salt content, calorie count, cancer statistics for smokers, etc. etc. etc.--but if the product is legal, then nobody should be taxed or discriminated against in any way for using it. I have no problem with taxes being imposed on the products themselves as the people have the option of using the product or not.
I don't want the government providing health insurance in any form, but if it does, then it should do as the private sector does. If you smoke or are overweight etc., you pay a higher premium than those with healthier lifestyles.