The latest example: New York's health commissioner is making a pitch to start adding a special tax on non-diet sodas. Here's the N.Y. Times article about it.
When it comes to food, government's role should be limited to the following:
1) Inspect and monitor industrial and retail food preparation for safety and hygiene standards; and
2) Ensure that farmers, food producers and food retailers provide complete, accurate information on the ingredients and methods used to produce or prepare their products.
If there's some other role that government should play, I sure as hell can't think of it. The same politicians who whine about sugar/obesity and foie gras are the same people who are willing to consider watering down the standards for "organic" to benefit their campaign contributors and friends.
I don't think the average politician or government bureaucrat gives a hoot about the public health. Their real interest is public grandstanding and/or raising taxes.
Considering what a great job our politicians did policing the banking and securities market, why shouldn't we let them act like food police?