- Fructose is metabolized similarly to ethanol. Both can only mostly be metabolized in the liver, whereas glucose can be metabolized throughout the body. Both result in a storage as fat of a significant portion of the calories, possibly in the liver, where the fat causes long-term harm. Most of glucose on the other hand is stored in the liver as glycogen, which is not harmful long-term, and is the main source when you're eating a bunch of white pasta (glucose) storing up for a big race.
- If we just ate fructose from fruits we'd eat 10-20% as much as we do today. Plus fiber is protective against many of the negative effects associated with fructose. So fruit is probably on the balance still good for you or neutral in terms of the negative effects from fructose mentioned here.
- Fructose seems to suppress the post-eating dip in ghrelin levels, where ghrelin is thought to be important in encouraging us to eat--the "hunger hormone".
- Fructose doesn't cause a spike in insulin and reduces leptin, which he views as a negative, as it goes along with not discouraging further eating.
- He gave no evidence that glucose is good or beneficial, or reasons why glucose isn't a threat to increased risk of diabetes, etc. He's just chosen his battle as against fructose, as it's more winnable than against all sugar.
That last bullet is my conclusion/wrapup of his perspective. I think his points are valid, and his recommendations are good for an overweight person (ie, your average American), but he oversimplifies things to make his case simpler and stronger. If you're really trying to stay healthy, eating a ton of glucose is not a good thing--an issue he mainly skirts to keep the focus on fructose.