The toxic truth about sugar

I'm sure you mean sucrose and fructose as opposed to artificial sweeteners, and in respect to health issues you are right to be concerned.
If there was one thing, and one thing only I would advise to keep childrens' weight under control, it would be to stop or severely restrict the consumption of soft drinks (on a personal basis). Just one small can or bottle a day will contribute nearly 16lb of body fat a year. Observing children going to and from schools where I live you cannot help but notice the casual normality of the ubiquitous can of 'Coke' etc.
Robert Lustig is the daddy where the subject is concerned, his viral video 'Sugar the Bitter Truth' has done more than any to spread the word that sugar, especially fructose, is a hepatotoxin, that should be avoided in its unnatural, processed, and concentrated froms. There are obese children now with non alcoholic fatty liver liver disease - when they get to the age to legally drink alcohol the combination can easily be imagined.
As to taxing sugar it's a nice idea, but the public will never wear it. You only have to look on youtube at the vitriol expressed towards an endocrinologist treating obese children (Lustig) to see that a sugar tax would never work. What might make a difference (in the States at least) would be to dump the subsidies that the corn growers enjoy. Somehow I can't see that happening anytime soon.