Even off of food stamps, the quality of food people are consuming under the guise of "healthy eating" is still causing issues.
How do you purpose educating the public, when every person thinks they are a doctor, an economist, a CEO, and an expert (whatever)?
How do you purpose to deviate the course of consumerism that has so obviously extended to our food consumption.
I would DEFINITELY like to see a viable alternative to a tax on soda, but in the real world, one isn't possible until folks realize they aren't the above (doctor, economist, etc)...
Read up on priming and you will see what the healthcare industry is up against in helping people who are suffering and preventing others from doing so.
When I was in college, the London congestion problem was something we studied, which is what (to me) a soda tax would be in the spirit of.