Experience has shown that consumers do not always use their freedom to make healthy choices. So a regulation that is based on science and in the best interests of the consumer should not be interpreted as an unwarranted intrusion into personal lifestyle choices.
Is the freedom to choose unhealthy food that difficult to forfeit?
Which reminds me of a comment I once heard another doctor make on CNN regarding smoking: "People who are making decisions for themselves don't always come up with the right answer." In other words, freedom is all well and good, as long as people use it to make exactly the same choices I would make. This seems to be one of the main lessons taught in schools of public health.
[Thanks to Audrey Silk for the tip.]