tag:blogger.com,1999:blog-5995754777906978314.post2956582958916012031..comments2023-10-20T05:56:15.365-07:00Comments on Evolving Health: What journalists should know before writing about fructophobiadaviddespain.secrethttp://www.blogger.com/profile/13271527839470084409noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-5995754777906978314.post-2474525809371863352013-02-01T17:34:06.178-08:002013-02-01T17:34:06.178-08:00Thank you. Very timely discussion.
Lustig's d...Thank you. Very timely discussion.<br />Lustig's dismissal of exercise as important in weight control is counterintuitive and in conflict with population studies and everyday experience, but the calories burned during exercise are indeed fairly minimal. Can David or someone summarise the metabolic reasons why exercise is indeed important to prevent and treat weight gain? <br />Lustig also does not believe that Calories consumed should balance Calories burned. This is contrary to both the laws of thermodynamics and nearly all known metabolic and nutritional knowledge, yet he offers little evidence to support his extraordinary but appealing view.<br />I hope Australian journalists find your blogs before Lustig's book is released here.<br />(I have no conflicts of interest to declare) myocytehttps://www.blogger.com/profile/04870128766983723129noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-59878130775305130602013-01-24T17:28:02.303-08:002013-01-24T17:28:02.303-08:00Diana,
Oops! I knew that. I'll change it. Th...Diana, <br /><br />Oops! I knew that. I'll change it. Thanks for letting me know. <br /><br />Daviddaviddespain.secrethttps://www.blogger.com/profile/13271527839470084409noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-56876843850631335592013-01-24T16:57:35.435-08:002013-01-24T16:57:35.435-08:00David, "illicit attention" - illicit mea...David, "illicit attention" - illicit means illegal. I think the word you want is "elicit." Sorry, I am a former copy editor.Dianahttps://www.blogger.com/profile/00302261963164621064noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-19656823703252946622013-01-22T19:37:27.897-08:002013-01-22T19:37:27.897-08:00Thank you for this wonderful insight, Professor Fe...Thank you for this wonderful insight, Professor Feinman. If I get a chance, I'll write something up about it. <br /><br />FYI - For those of you who don't know him, Richard Feinman is professor of Cell Biology at SUNY. <br />daviddespain.secrethttps://www.blogger.com/profile/13271527839470084409noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-36759571572754821722013-01-22T14:36:16.789-08:002013-01-22T14:36:16.789-08:00I removed my previous comment because it was off-l...I removed my previous comment because it was off-list to David and slightly off-topic and duplicated some of the above. <br /><br />The question was about ethanol and fructose metabolism which is one of the great inaccuracies in Lustig's story. I mentioned that I had published an article showing the similarities and differences between the oxidation of ethanol as a food and oxidation in glycolysis in which both glucose and fructose participate. The paper suggested that ethanol metabolism was a good transition between organic and biochemistry.<br /><br />https://dl.dropbox.com/u/37202414/JCE-ADH.pdf<br /><br />Bottom line, if you know a little biochemistry: ethanol is oxidized to acetaldehyde which is then oxidized to acetic acid and that, in turn, is converted to acetyl-CoA and goes into the TCA cycle. The oxidizing agent is NAD+ as in many redox reactions in metabolism. I have a blogpost that may make this clearer http://wp.me/P16vK0-eY<br /><br />The key oxidation in glycolysis is the conversion of glyceraldehyde-3-P to 3-P-glyceric acid, analogous to (but more complicated than) the second step in ethanol oxidation. The difference is that in glycolysis it is done in two steps. Why? The idea is that you learn in sophomore organic that aldehydes are easily oxidized. So NAD+ + ethanol is energetically very favorable. Where does the energy go? There is no mechanism for capturing the energy and it is wasted as heat. For glycolysis, however, instead of letting the oxidation run straight through, the enzyme (Ga-3-P dehydrogenase) uses the energy of oxidation to make a high energy compound 1,3-bisphosphoglycerate. This compound can then be coupled (catalyzed by 3-P-glycerate kinase) to the synthesis of ATP. So the combination of the two steps allows some of the energy to be captured. <br /><br />Both fructose and glucose feed this reaction in glycolysis which is a different pathway from the ethanol reaction. Another important difference is that, at some point, the NAD pathway cannot keep up with high ethanol and it becomes a drug or toxin, if you like. There is a separate oxidative process, the P450 system, which might reasonably be called detoxification. No such system exists for fructose as far as I know. Calling fructose a toxin doesn't have an obvious correlate in metabolism.<br /><br />feinmanhttps://www.blogger.com/profile/15255697993561879086noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-34069546737727762472013-01-20T15:51:10.586-08:002013-01-20T15:51:10.586-08:00This comment has been removed by the author.feinmanhttps://www.blogger.com/profile/15255697993561879086noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-5433818675123418442013-01-20T15:50:17.289-08:002013-01-20T15:50:17.289-08:00My original critique at http://wp.me/p16vK0-6W des...My original critique at http://wp.me/p16vK0-6W described fructophobia as a threat and an opportunity. If people use the book to find out about metabolism it will have been an opportunity. For example, the metabolism of fructose has hardly anything in common with the metabolism of ethanol but if the question is used as a way of finding out about how they are really metabolized that will be a big step forward. If we ask the really interesting questions: Glucose and fructose are interchangeable and they come together at the level of the three carbon compounds, the triose-phosphates. in those cases where fructose has a unique effect, how does the cell know where the carbons come from, or does it?. If we can use the fructose case to expand our knowledge of metabolism, that will be a great thing. <br /><br />On the political end, if fructophobia can lead us into real use of carbohydrate restriction that will also be a benefit. I am concerned that when you give up on science, you never know where it will go so progress will probably be slow. The low-fat-cholesterol thing is dying a slow and agonizing death because of having given up on science early on.feinmanhttps://www.blogger.com/profile/15255697993561879086noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-17006907269590994662013-01-20T14:17:06.308-08:002013-01-20T14:17:06.308-08:00Nicely done David!
I have one question: Where is...Nicely done David!<br /><br />I have one question: Where is the academic press book on the topic? And all I have to say in answer to that is that he could not write one. Which to me is QED.<br /><br />Are there no fact checkers at UC Davis that might have stopped his juggernaut of misinformation ... like, say at the UCDavis produced YouTube video level? For shame!CarbSanehttps://www.blogger.com/profile/17739915307890592327noreply@blogger.comtag:blogger.com,1999:blog-5995754777906978314.post-91636399239509636142013-01-20T10:23:58.769-08:002013-01-20T10:23:58.769-08:00I have to say, I completely disagree. I've tal... I have to say, I completely disagree. I've talked to Lustig and checked out a lot of scientific research on the topic. My own article on obesogens in Environmental Health Perspectives mostly focused on chemical obesogens (mostly EDCs) but in my interviews that didnt make it into the piece, I did research High-fructose corn syrup which is also an obesogen that can alter the epigenome of unborn children, according to some research. Here's a link to the PD of my article http://www.wendeeholtcamp.com/Obesogens-EHP.pdfAnonymoushttps://www.blogger.com/profile/17222740854325977352noreply@blogger.com