I just want to take the last sentence first: The government did do exactly that. They took 'science' and used it to justify a low fat, low protein diet. Michelle Obama was at the forefront of forcing us into 'healthier' diets for our kids. And it was under the guidance of a dietitian following government guidelines. This suggests we do exactly the same. (shoulders slump.)
ON THAT: I am fine with some tax changes, but more in the removal of subsidies for corn, ethanol and related, instead of taxing the population for a sugar tax. Right now sugar production would crash in the US if we did play around with the tax structure too much, we would lose to Brazil and other countries fairly quickly, and you would have a lot of angry farmers. It unfortunately reminds me of a comment in Accelerando about buggy whips.
http://www.antipope.org/charlie/blog...celerando.html (it is in the Lobsters chapter - and is a bit adult.)
To tackle this properly, we have to look at a full restructuring of a large portion of our farming - so much is dedicated to high carb food. But we shouldn't hold onto sacred things like the buggy whips industry when the automobile has started becoming popular. So the real work comes in retooling and retraining at the food production level, far more than tax. If not, you break the thing you need, right when you most need it.