tag:blogger.com,1999:blog-8922603303635470029.post5163191952447683778..comments2023-06-25T04:21:43.376-04:00Comments on Pedal and Wrench: Fructose and Glucose discussionAnonymoushttp://www.blogger.com/profile/02365851588737326710noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-8922603303635470029.post-31675531622747340462022-07-17T15:41:53.492-04:002022-07-17T15:41:53.492-04:00Nicce blog you haveNicce blog you haveMartin Evanhttps://www.martinevan.com/noreply@blogger.comtag:blogger.com,1999:blog-8922603303635470029.post-29705657527759423992008-12-16T11:47:00.000-05:002008-12-16T11:47:00.000-05:00This is a freat analysis, though horribly boring. ...This is a freat analysis, though horribly boring. Couldn't you have added some pithy jokes or something? <BR/><BR/>Seriously though, I'm with you on most of this except for the fructose part. I have a feeling we're missing something. Specifically, if you consider the fact that one is consistently in a sugar deficit while racing (see TMB's comment about uptake), there will always be a net release of glycogen from the liver to the blood, so the fact that fructose is acting to facilitate glucose storage in the liver probably doesn't matter. The liver is the largest single reservoir of sugar in the body, holding 10x more glycogen by mass than muscles (it's equivalent in glycogen storage to about 30lb of muscle), so I would expect that keeping it well charged during exercise, even if it means using fructose, it beneficial. <BR/><BR/>Regarding the post-race eating, I get your point about the glucose before fructose, but I have read that the window for efficient glycogen storage after exercise is about 45min. After that time, it is much more likely that an excess of calories will be stored as fat. This would indicate that glucose + fructose shold be consumed immediately post-race, and more slowly metabolized carbs should be consumed after the 45min window.Anonymoushttps://www.blogger.com/profile/02365851588737326710noreply@blogger.comtag:blogger.com,1999:blog-8922603303635470029.post-85355125359512551932008-12-12T11:22:00.000-05:002008-12-12T11:22:00.000-05:00Som studies pointed to results that fructose+gluco...Som studies pointed to results that fructose+glucose can be more effective at increasing blood CHO levels than pure glucose. However, other studies also suggest that the limiting factor of sugar uptake may be occurring in the intestines, and that the problem is that glucose is not so quickly passed.<BR/><BR/>The glucose vs. glucose+fructose studies would have been well served by providing an isocaloric comparison to glucose + matlodextrin. Maltodextrins are more reportedly absorbed into the bloodstream more quickly than glucose, suggesting that the comparison to straight glucose is somewhat irrelevant, especially since no sports drink uses pure glucose.The Pedalhttps://www.blogger.com/profile/11548544991983892637noreply@blogger.comtag:blogger.com,1999:blog-8922603303635470029.post-28591526159588162802008-12-12T10:09:00.000-05:002008-12-12T10:09:00.000-05:00After "...46/Latest_Research" it should continue "...After "...46/Latest_Research" it should continue "_on_Carbohydrate_Recommendations_During_Exercise.aspx"Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8922603303635470029.post-81098945051436837242008-12-12T10:05:00.000-05:002008-12-12T10:05:00.000-05:00It seems I did not correctly copy/paste the link: ...It seems I did not correctly copy/paste the link: http://www.powerbar.com/articles/46/Latest_Research_on_Carbohydrate_Recommendations_During_Exercise.aspxAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-8922603303635470029.post-53308492924168736692008-12-12T10:00:00.000-05:002008-12-12T10:00:00.000-05:00It is indeed a fascinating topic. I lift my virtua...It is indeed a fascinating topic. I lift my virtual hat for the effort you put into this undoubtedly important matter for endurance racing; especially since it seems that there are a lot of myths and marketing propaganda out there. <BR/><BR/>While you argue convincingly, at least to me as a non-expert, one area you did not address is how many carbs at what speed the body is actually able to absorb. In this light, what do make of studies* that claim that glucose uptake is limited to about 60 grams per hour. But, that a glucose/fructose mix (in a 2:1 ratio) allows you to consume about 90 grams of carbs per hour? <BR/>-TMB<BR/><BR/>*A commercially-inspired summary of this study can be found here: http://www.powerbar.com/articles/46/Latest_Research_on_Carbohydrate_Recommendations_During_Exercise.aspxAnonymousnoreply@blogger.com