[hristov]

There is an explanation. I urge you to watch the entire video. The problem with fructose is that the liver has only a limited ability to properly process it. This if you get too much the liver processes a lot of it through the wrong pathways, and that causes all types of chaos.

There are a couple of differences with natural fructose. First natural fructose almost always comes with fiber. The fiber if processed at the same time as the fructose allows the liver to properly process more fructose. This is because the fiber provides certain nutrients which allow the liver to process more fructose along the proper pathways.

Second, natural fructose is usually in plant cells. In order for us to process these, we much first break down the plant cells in our stomach. This takes some time, so the effect is that the natural fructose does not hit the liver in the same speed and concentration as refined fructose.

This all has scientific support by the way. Lustig mentioned a study in old Caribbean sugar plantations. There they tracked the health of the masters and workers. It turned out that while both the masters and workers ate mostly sugar, the masters had a lot of health problems associated with obesity and diabetes, while the workers did not. The difference was that the masters ate refined sugar, while the workers mostly just ate raw sugar cane.

There was another study in japan, where scientists tried to give people massive amounts of sugar in the form of apples. These people did not have any of the problems associated with high sugar intake.

[raverbashing]

I think you're almost there

Fructose is fructose, there's no "natural fructose" however it's one thing to eat it pure, another one in a fruit

"The problem with fructose is that the liver has only a limited ability to properly process it."

Correct, glucose can replenish muscle glycogen, fructose can't (the liver produces both types of glycogen) - http://www.ncbi.nlm.nih.gov/pubmed/3592616

"This is because the fiber provides certain nutrients"

Fibers, per definition are not digestible but are other things that may happen http://en.wikipedia.org/wiki/Dietary_Fiber

And of course glycemic index may be a problem with sugars as well.

[_delirium]

Fructose is fructose, there's no "natural fructose" however it's one thing to eat it pure, another one in a fruit

That I can buy. What I'm more skeptical of is that there's a distinction between "manufactured" and "natural" fructose once both have been concentrated and are used as additives to sweeten other products. Eating a pear is one thing, but I'm less sure that a "naturally sweetened" product which has been sweetened with concentrated pear juice or a similar fruit-based sugar extract is really more healthy than the same product that has been sweetened with more conventional "manufactured" sugars. I don't doubt that eating an actual fruit is almost certainly better than either one.

[sizzle]

I've come to learn that "natural" is a marketing weasel word that adds nothing of value to describing a product.

[stefantalpalaru]

There's only one type of glycogen that's stored in different places. The article you linked only refers to "rapid glycogen restoration". Don't assume from that that the liver can't produce glycogen from fructose.