Regarding sugar vs. fat: large amounts of saturated fats are known to be unhealthy. In small amounts, sugar can even be healthy, e.g. after exercise.
One problem with taxes on addictive substances is that they have little effect on consumption behavior. A higher tobacco tax makes smokers poorer, but only very few will smoke less as a result.
One problem with taxes on addictive substances is that they have little effect on consumption behavior. A higher tobacco tax makes smokers poorer, but only very few will smoke less as a result.