Should we have a junk food tax?

I see what your getting at but considering 90% of the food and products we encounter are filled with "junk", it wouldn't be so clean of a tax. Even vegtables aren't very natural unless they are organic. In all honesty if we rose taxes to 70% for all citizens we could easily fund a strong health care system as well as greatly improve our schools. Or we could just cut funding from over-inflated organizations like NASA, who spent 3 billion dollars to crash on Mars. I like science and believe in exploration as much as the next guy, but between health care and pictures of deep space and rocks from far planets it isn't my first pick. Then again do we really want government supported healthcare? They have trouble taking care of roads, do you really trust them with your life.