Junk Food is Not a Right

As is typical, libertarians confuse freedom with entitlement. You are free to eat what you wish on a school campus, and it would probably exceed the constitutional authority of Congress to tell you what not to eat. But, at the same time, you are not free to buy whatever you want for lunch at school. And yes it certainly suits the authority of Congress under the commerce clause to regulate what children eat in school, seeing as how obesity is a national problem that costs federal taxpayers. Clearly there are some areas of regulation in which it is more appropriate to permit the states to take a paramount role, where states have varying approaches to unique problems that they face (as with land use regulations, for example.) But when it comes to what kids eat in school, there hardly seems to be much of a state sovereignty argument for permitting states to adopt wildly different approaches.