Glyceroneogenesis v. Taubes
My greatest criticism of Taubes is that despite several years of "exhaustive" research, and a deluge of references in his book, the bulk of his "Adiposity 101" is either unreferenced, or based on decades old physiology texts and papers.
In this lecture (Slide 48 at around 46 min in) is his discussion of glycerol-3-P. Taubes is a master of stating facts ... in a misleading way that (1) leads the listener/reader to incorrect conclusions, and (2) enables Taubes to use the "I never said that" out when challenged.
He first quotes a 1970's text on the Fatty Acid Cycle and shows an updated text of similar. In both he highlights the need for glycerol-3-P to esterify FFA's to triglycerides. This is true.
However on Slide 48 he presents a bunch of cobbled together "facts" that are either not considered settled science or are taken out of context. And I note that while he now (2009) lists glyceroneogenesis on his slide, the word never passes his lips. He jumps right over this bullet point on the slide!! I cannot help but think that he has been informed since the 2007 publication of his book that such a metabolic path exists. But since acknowledging it would probably require scrapping this entire section of his lecture and derail his money train, he prefers to include a term on a slide in a long lecture and hope nobody notices. Since this is a term few if any have a clue about, he's successful, and anyone who is reading his slides is likely to take at face value his assertion that it is only a small amount. If not outright deception in the name of financial gain, Taubes is at the very least displaying a degree of willful ignorance.
But maybe this whole glyceroneogenesis stuff is too recent to address, so Taubes is just relying on the old info b/c nothing concrete has come about. Well, in addition to the comprehensive overview of the Fatty Acid - Triglyceride Cycle including glyceroneogenesis (2003), I recently came across this:
Glyceroneogenesis comes of age 2002
The science of glyceroneogenesis was being elucidated around the time that, presumably, Taubes began his lengthy research efforts following his Big Fat Lie NYT article. How did he miss all of this? And how, in 2009 can he continue to ignore this.
As I've blogged on previously, the low carb nutritional state mimics the fasted state. There is no reason to believe that the processes upregulated similarly for fasting and LC "fed" (gluconeogenesis, increased ketone formation, etc.) state would exclude glyceroneogenesis. Indeed there is every indication that they are upregulated.
UPDATE: It just got worse as I got my Sony ebook software working again to search GCBC for glyceroneogenesis. Well, it's nowhere in the text, but it is right there in the title of one of his references. The 2003 article linked to above. I'm left to conclude this man is totally bereft of intellectual honesty.
But maybe this whole glyceroneogenesis stuff is too recent to address, so Taubes is just relying on the old info b/c nothing concrete has come about. Well, in addition to the comprehensive overview of the Fatty Acid - Triglyceride Cycle including glyceroneogenesis (2003), I recently came across this:
Glyceroneogenesis comes of age 2002
The science of glyceroneogenesis was being elucidated around the time that, presumably, Taubes began his lengthy research efforts following his Big Fat Lie NYT article. How did he miss all of this? And how, in 2009 can he continue to ignore this.
As I've blogged on previously, the low carb nutritional state mimics the fasted state. There is no reason to believe that the processes upregulated similarly for fasting and LC "fed" (gluconeogenesis, increased ketone formation, etc.) state would exclude glyceroneogenesis. Indeed there is every indication that they are upregulated.
UPDATE: It just got worse as I got my Sony ebook software working again to search GCBC for glyceroneogenesis. Well, it's nowhere in the text, but it is right there in the title of one of his references. The 2003 article linked to above. I'm left to conclude this man is totally bereft of intellectual honesty.
Comments
You and I seem to have the same obsessive interest in glyceroneogenesis ;). It would probably interest you to know that Taubes recently put out a lecture (April 2010) where he fully admits that glyceroneogenesis is a potential source of AGP during low carb dieting. I can only speculate as to why he didn't mention or know about this metabolic pathway sooner. When I discovered several years ago the 2003 paper you referenced listed as a source in his book, I was a bit befuddled to say the least. I hate to accuse anyone of dishonesty,and there could be another more forgivable explanation, but damn, that did not look good...
This is a very informative blog! I hope you keep writing!
Glyceroneogenesis is discussed around the 55 minute mark.
I was absolutely FLOORED when I searched the ebook and found that reference in GCBC. Thanks for the link to his most recent lecture -- I've resisted watching these up until now but will watch his updated lecture and comment on it.
His weasly words in the new lecture are telling -- he claims to have been informed by a smart young biophysicist of some new info but then glosses over glyceroneogenesis -- body language and speech patterns are telling there. One problem, he DID have that article when he wrote this book! Any *exhaustive* research would have turned up many more. He's still peddling this theory as if it were fact. Either he didn't read the article he referenced for *something*, or he didn't understand it, or he ignored it. Any of the preceding do not shed a good light on Mr. Taubes.
I go by Low Carb Cheater on Jimmy Moore's discussion forum and read a lot of others though don't participate significantly elsewhere. I should change my moniker so that I can be addressed but don't want to use my "real name". Will have to think on that :) Should also update "About Me" to give a little insight into my background.
For some reason, Taubes' omission of glyceroneogenesis doesn't bother me as much as his followers' (for lack of a better word)refusal to acknowledge it when told about it. I have blogged about it twice and I know that many people have looked at those posts. I think it's safe to assume that many of the people reading are very interested in low carb diets and have read GCBC. I've also left comments on several low carb forums describing this alternate pathway in threads about glucose being necessary for G3P production. The silence was deafening. And I'm certainly not the only one out there touting this information on the web. It's there to be found and has been for several years now. But it's largely ignored! Put "low carb" and "glycerol phosphate" into Google and you'll get TONS of hits. Add "glyceroneogenesis" and the hits drop dramatically. Strange and frustrating!
I think this guy's ego has eclipsed his integrity.
http://weightology.net/?p=251
http://weightology.net/?p=265
Do you plan to migrate the fructose lecture from your old blog over to your new site(s)?
I've been perusing your blog and you do an outstanding job of exposing some of the LC dishonesty out there
And the process of glycerneogenesis while it will allow for fat storage sans carb intake will not result in obesity.
This is not the issue here, but this tactic is not unfamiliar to those who have followed discussions. First it's whatever the claim is, when claim is proven false the claim is changed to something along these lines.
The claim is dietary carb is the major source of G3P and that G3P drives esterification. Read the two links here (one of which Taubes references) and my blog posts on ASP. Acylation is stimulated by dietary fat (chylomicrons) and ASP can stimulate glucose transport too. Insulin has little to do with the esterification, it does have an important role limiting lipolysis so that the bloodstream is not flooded with NEFA.
Thanks for contacting GT for me. I will email him in hopes of getting clarification in the next day or so, but that will have to wait until I have time to put together a well linked "argument" for him to consider.
All the evidence needed to show how wrong headed he is about this issue is available on my blog.
Body fat levels are to a VERY large extent GENETICALLY determined.
Anthony Colpo and his cohorts REFUSE to see the knowns about the the etiology of obesity are FAR LESS than the UNKNOWNS.
Calories are only one factor among dozens, upon dozens, upon dozens, upon dozens.
GENUINE science has turned up gut microbiota, common cold viruses, medications, genetics, toxins, malnutrition and many more things.
The phenomenon of obesity is far more complex than Colpo et al will ever admit.
GENUINE science does not talk like Colpo et al. I credit Gary for EXPOSING how the Caloric Hypotheis is dead.
Blood insulin levels are the same everywhere in the body , so I do not believe the insulin hypothesis can explain severe LIPODYSTROPHY - but NEITHER can the caloric hypothesis.
Science needs to find an alternative model. That is the problem. GENUINE SCIENCE is a work in progress. Obesity is FAR from figured out.
P.S. I DO credit Anthony for jumping out of that plane and genuinely liked that video. He has tremendous courage. I would not even go n a steep roller coaster. LOL !
An understanding the fat cell lipid exchange mechanism is ESSENTIAL to what we need to understand.
NO ONE has a complete understanding of what causes obesity's onset. To do so would REQUIRE a COMPLETE understanding of human cellular metabolism Science does not understand cellular metabolism that well - only bits and fragments. NO ONE has the secrets to long term fat loss- or even short term. Most fat people I see who "lose weight" just look like smaller version of themselves. Still have their saddle bags, but a thinner upper body and lost muslce.This is not a criticism. They are VICTIMS of BAD advice.
The cure for morbid obesity does not exist. People like Manuel Uribe will not be helped until we make progress.
You and Colpo can keep sticking fingers in your ears, my blog has NUMEROUS links to GENUINE SCIENCE from ScienceDaily DISCREDITING the both of you.
We have are so far removed fromn solving morbid obesity it is not even funny. There are MANY more poeple almost as heavy as Manuel. 800 plus pounders.
You are very unfamilair with the literature.The Caloric Hypothesis is DEAD
WATCH URGELT'S obesity video - READ the COMMENTS.
GENUINE obesity science ADMITS there are VAST UNKNOWNS. Krieger , Colpo and you do NOT.
You need an education baldy.
Look toward GENUINE SCIENCE not Colpo's site to guide you about obesity.
The commonly held belief systen and ASSUMPTION that if we just eat less and exercise more is COMPLETELY AT ODDS WITH VERY COMPELLING SCIENTIFIC EVIDENCE that body fat levels are to a VERY signficant extent GENETICALLY DETERMINED.
The hertibility of obesity is ONLY surpassed by height - and perhaps equal to it.
Friedman JM et al. Modern science vs the stigma of obesity . Nature Medicine 2004. 10 ( 6) : p. 563-9.
Maes H.M. Neale and L Evans Genetic and environmental factors in relative body weight and human adiposity . Behavior Genetics 1997. 27. : p.325 - 51.
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FRED HAHN: > And the process of glycerneogenesis while it will allow for fat storage sans carb intake will not result in obesity.
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Hey FRED: PROVE IT !!!!!!!!!!!
Or are you just fond of saying that, and NEVER DOING IT YOURSELF ?
to us, keep it up.
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