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Comment by symptic | Hacker News Reader

Lustig makes a few great points, but it's important to keep in mind there are some who argue he is a "fructose alarmist" and argue it's not as simple as "blaming fructose alone." A good quote from Alan Aragon: "I would add that fiber is only one of the numerous phytochemicals in fruit that impart health benefits. Thus, it’s not quite as simple as saying that fructose is evil, but once you take it with fiber, you’ve conquered the Dark Side."

Some links: http://www.alanaragonblog.com/2010/02/19/a-retrospective-of-...

http://www.alanaragonblog.com/2010/01/29/the-bitter-truth-ab...

http://www.bodyrecomposition.com/research-review/straight-ta...

I personally don't take sides with either. Like most things in the nutritional field, a healthy balance is more effective for me than trending behaviors and ideologies (i.e.: no-fat diet, "slow carb" diet, Atkins diet, etc.).

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Eating a fruit is not the same as drinking the equivalent amount of fruit juice along with some fiber for the same fructose load, because when eating a fruit the fact that the sugars are bound up in the fibers and must be broken down acts as a rate control.

It's a dose issue, but dose is both volume and absorption rate, and the absorption rate of fructose from free sugar is very fast, as it is not rate-regulated in the liver like glucose metabolism. This means it doesn't require as much refined sugar compared to sugar from fruit in order for your liver to spend some time with a dangerous fructose load;

-Refined- sugars are -especially- problematic, because of the absorption pattern. Simply combining free sugar with supplemental fiber mitigates some of the metabolic issues, but doesn't alleviate the problem.

If you watch Lustig he -does- say the fruit is fine, for this reason.

Whenever we find the chemical in a particular plant that is the one we like the most (and in rats, it's been shown that sugar&cocaine addicted rats prefer their sugar hit to their cocaine hit), extract it, and crystalize it, it's not surprising that it may be problematic.

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.

Yes, very large red/purple/green grapes without seeds are the common variety in stores in the US.

Perhaps the evolutionary fitness of grapes was independent of that particular characteristic.

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