There are dozens if not hundreds of researchers who have become convinced that fructose is causing our increase in the metabolic syndrome and nafld. And I don't think Dr. Lustig is ax-grinding or that he did a private theoretical study.
He is a professor in Pediatrics in the division of Endocrinology so he is an expert on this stuff including the physiology and bio-chemistry. And he is good at fitting together the pieces of the puzzle from lots of OTHER people's research studies, that explain the mechanics of how this all this is happening.
Feel free to watch some his educational seminar while you surf, and see if he doesn't convince you. I found him fascinating and he kept my interest thru the whole thing. If he doesn't keep your interest, fine, turn him off and call him a quack.
http://www.uctv.tv/search-details.aspx?showID=16717
If that plays jerky, you can download the file first before playing it...
http://podcast.uctv.tv/vod/16717.mp4
I AM aware that Princeton had a recent study that concluded that HFCS was the culprit and not the fructose in regular table sugar, but that study was done with rats and has yet to be confirmed by others, or in humans. (I wondered if the sugar industry had any connection to Princeton - a lot of researchers get influenced by lobbyists)
Lustig does not believe that is true (based on his experience with humans). He believes that table sugar is quickly separated into its two molecules "in two seconds flat" by an enzyme in our gut called sucrase, and THEN the fructose molecule from sugar is identical to the free fructose molecule from HFCS, as it heads to our liver.
Sucrose intolerance (also known as Congenital Sucrase-Isomaltase Deficiency (CSID) or Sucrase-isomaltase deficiency) occurs when sucrase is not secreted in the small intestine. With sucrose intolerance, the result of consuming sucrose is excess gas production and often diarrhea and malabsorption.
Anyhow, the point is this doesn't happen until the small intestine is reached. If a mix of sucrose-containing confectionery and "healthy" fibrous foods is consumed, it isn't going to be "two seconds flat" from the point of tasting the sugar before getting it in the bloodstream as fructose. There's that pesky stomach in between, letting partially digested food out into the duodenum little by little through a sphincter. Not even liquids get a quick pass into the duodenum, because the stomach lining is a sponge for getting their water content into the bloodstream.
This ain't even medicine, it's high school biology.
AND, HFCS tends to have a higher share of fructose than does sucrose. If fructose is the problem ingredient, HFCS is a bigger problem than sucrose.