Did you listen to the linked MP3? If so, I'm not sure how you can listen to that and conclude he's "blaming fructose alone". I'm up to at least three times he's clearly explained why that's not the case. And I don't mean "mouthing words about it then blaming it anyhow", I mean, explaining the ways in which things work together to cause obesity, and how fructose is only the most effective member of a group of 4 foods, and so on.
I really think people really ought to go primary sources and stop listening to people summarizing summaries and then launching devastating assaults on strawmen.
And Lustig, in this podcast, talks about how fiber and fructose tend to go together in nature, which is why whole foods are good as they usually have both. He gives two examples where they don't though... grapes and honey. But he says that honey is protected by bees. But no answer for why grapes make it easy to get fructose without fiber.
Grapes have been domesticated for thousands of years, and at every step the goal has been to maximize fructose and minimize fiber, most notably in making the seedless varieties that comprise the vast majority of table grapes sold today.
At this point, who knows what grapes were originally like? Of course, we know they had real seeds and I'm guessing they weren't so plump and thin-skinned. So maybe they had a much more commendable fiber-to-fructose ratio.
Today, table grapes are just glucose and fructose water balloons.
Wild grapes tend to have large bunches of really small fruit with a few seeds, if I remember right. We had some in our backyard in Livermore years ago.
Are you guys talking about the huge, swollen, purple grapes that are incredibly sweet and juicy? In New Delhi, you only find those grapes at large supermarkets. Most grapes sold here are exactly what you described: large bunches of really small fruit. No seeds, though.
I really think people really ought to go primary sources and stop listening to people summarizing summaries and then launching devastating assaults on strawmen.