Broccoli and the constitution

A law professor has made the argument that not only can Congress mandate all US citizens must purchase health insurance, but by extension, can force everyone to buy broccoli!  Sounds like the solution to all of the produce industry's woes.  We can legislate a healthy diet.  But wait, there is a catch.  The argument is Congress can mandate health insurance (and broccoli) because both fall under its authority vis a vis the commerce clause.  This allows Congress to impose regulations on anyone who has anything to do with interstate commerce.  Since we all participate in this activity, willingly or not, we are all subject  to the regulation from Congress.  The kicker, according to this expert is that while we can be forced to buy health insurance or vegetables, we cannot be forced to use the insurance, or eat the vegetables, as this would be an infringement on our liberty.  As he goes on to say, the constitution does not protect us from stupid laws, which the broccoli law would be, but it does provide the remedy of elections.  As much as I love broccoli (I harvested about 25 lbs. worth last night) I would not want to run for office using the platform of forced broccoli or vegetable purchases, especially here in the North Country.  That would be political suicide.