The crux of the piece, as I heard it, was that sugar is about as bad as fat when it comes to causes of heart disease and heart attacks, that HFCS is, in fact, worse than cane sugar because of the way the liver processes them, AND that the brain responds to sugar about the same way it does cocaine, and proves to be about as addictive.
So, toxic might a little strong, but when the doctors that worked on these studies recommend no more than about 100g/day of added sugars in your diet, less than what's in a can of soda, "large quantities" may not mean what you think it means either.
For starters, there are pathways for breaking down fat, storing it, and burning it in the body.
Secondly, refined sugars incorporating fructose are all about equivalently bad.
Thirdly, when you go over a certain smallish amount of fructose, your liver has to respond to eliminate this 'toxin' from the body, which produces really bad LDL cholesterols, which contributes to stroke and heart disease risk.
On the basics, and this is the slightly confusing thing for those new to this topic, your body really only uses glucose sugar directly. There is a whole mechanism dedicated to storing glucose as glycogen (in the liver), and then retransforming it and burning it when you need energy. This does not work with fructose, which has to be transformed to fat, stored, then burned later.
This nutritional disadvantage of fructose would be enough for me to stop eating it, even without all the other problems.
The US move from complex carbs like starch that can be broken down to glucose in the body and readily used by cells, to poorer quality foods with much added (cheap) fructose, has massively increased the amount of fructose we ingest, and according to Lustig, increased the damage to our bodies.
I personally don't eat refined / fructose sugar except in fruit and small amounts of honey or jam, and the times when I have a something like a cookie with lots of sugar, I really really feel the effects, the worst being a sort of sugar come-down that manifests as extreme irritability.
So, toxic might a little strong, but when the doctors that worked on these studies recommend no more than about 100g/day of added sugars in your diet, less than what's in a can of soda, "large quantities" may not mean what you think it means either.