[bittired]

This is already done through the WIC program. If you look at the shelves in the grocery store, you'll see the WIC label on certain foods. It does not stop poor food choices. The only way to make it work would be to shutdown all fast food restaurant and pull all crap off the shelves in the store, and that will never happen. Anything that can be abused to get more caloric intake for less money will be abused.