In the Competitor Radio interview on 29 March, Bob Babbit interviewed Asker Jeukendrup, a well known exercise physiologist and advisor for Chrissie Wellington. Asker discussed the results of his latest research on carbohydrate intake during exercise, and stated that by using a ratio of glucose - fructose (roughly 2:1) the absorption rate rose by 75%. Has anyone tried this ratio out during training and/or races, and if so, what products or homemade ingredients were used? Asker also indicated that Chrissie uses his carbs ratio with obviously good results…
I saw the title and assumed you were discussing Holley 850 double pumps…
Asker also indicated that Chrissie uses his carbs ratio with obviously good results…
Crap, now that Chrissie’s secret has been revealed, the womens race will NEVER be the same.
The papers are not all new actually, but here they are
http://www.ncbi.nlm.nih.gov/pubmed/15946410
http://www.ncbi.nlm.nih.gov/pubmed/16322366
Actually a friend and colleague of mine attended a talk by Asker J. a couple of weeks ago, and the first question was about gastric issues with the GL+FR combo, since the it is well known that you don’t really want to go with fructose only unless, you intend to lose some weight 
Anyhow, the combo seems to limit significantly gastric issues…
That interview really caught my attention. I thought the science made good sense. Also, he was not plugging any specific company. I plan to experiment on my trial sample of one in training.
I wonder is Asker J. has tried it himself during an Ironman. He’s raced a few (Hawaii included)…
I know one person on this forum who works with him who may be able to say…
the receptors/transporters that move the different carb molecules around are different therefore allowing for more to be moved into the system… i.e. they aren’t both competing for the same taxi
Thanks for posting those two documents. The writer is very straight forward and to the point.
What’s a practical way to test it for yourself?
I’d suggest to actually do it progressively, start with 1g/min, and move up, just to ensure no GI issues. You don’t want to be 45min run away from home and major GI problems
In the Competitor Radio interview on 29 March, Bob Babbit interviewed Asker Jeukendrup, a well known exercise physiologist and advisor for Chrissie Wellington. Asker discussed the results of his latest research on carbohydrate intake during exercise, and stated that by using a ratio of fructose - sucrose, (roughly 2:1) the absorption rate rose by 75%. Has anyone tried this ratio out during training and/or races, and if so, what products or homemade ingredients were used? Asker also indicated that Chrissie uses his carbs ratio with obviously good results…
It’s glucose (not sucrose) and fructose and the studies were done using 2/1 or 1/1 glucose/fructose if you read the posted abstracts.
Funny…I missed that in the original post…
Although going out on a long run with a 2:1 ratio of Fr/Gl could be interesting (don’t forget toilet paper).
I heard this interview too and was actually very intrigued.
In my fist Ironman (Arizona) last November I ended up taking over 500 calories an hour on the bike and over 300 an hour on the run. I know this might sound like a lot but a coach I talked to told me this was the upper limit of what people can handle so I should start at the upper limit and if I have GI issues then start cutting back. I of course tested this relentlessly in my training and found that I had the ability to digest this many calories without any problems.
My Nutrition plan consisted of mix of Carbo Pro (Glucose) and Power bars and gels (mostly Fructose) so without knowing it I was getting slightly over 60g/h of Glucose and slightly over 30g/h of fructose.
This seemed to work really well for me as I never had any stomach issues and my energy felt very consistent throughout the day. I’m convinced that my nutrition plan is what allowed me to have the fastest armature run split of the day.
My suggestion to you would be to try and start training with this magical 2:1 Ratio (60g/h to 30g/h) and see how you feel. If your body can’t handle it and you get GI issues then you can start cutting back a bit but if your body can digest it then it’s only going to benefit you to hit that upper limit. Just make sure you test it time and time again before you use this plan in a race.
Oops, thanks for the correction, should have checked – my memory was a little foggy. I edited my original post.
I have not tried a glucose to fructose ratio. But, I have found that using a maltose,dextrose and sucrose combination works way better than anything else I have tried. For example I used to have troubles hitting 270 calories per hour on carbo pro (maltodextrin only) and often had some issues on the run (stiches/cramps). With the new combination, I can often average 350+ calories per hour which makes a big difference for me in terms of stamina.
I stumbled onto it when carboshotz used to make a drink. They went in a new direction, so we built Factor 9 Blend with Infinit. Not everyone likes it, but it is by far the most successful recommendation in terms of fueling I have made to other athletes.
One of the full papers is available at inifnitinutrition.com. I have been using infinit for several years – pretty much since the company started. As you could guess, they use this mixture of carbs, although they get the fructose from sucrose (=1glucose and 1fructose) rather than fructose itself, at least that’s what I gather from the ingredient label. (There are also other sources of glucose.) I don’t know the exact ratio. I did ~350 cals/hour in my only ironman (also several halves at 300-325) with infinit and it worked fine, although it’s fair to say that I have a pretty insensitive digestive tract. I enjoyed that podcast and was intrigued by some of the things he said, one of which was that the ability to assimilate calories does not scale as widely as body size/weight, so his calorie recomeendations didn’t swing as much as one might think. It’s well worth a listen…lots of food for thought therein.
Dan
Asker’s a good egg. It should be noted, though, that he found that the increased rate of whole-body carbohydrate oxidation that accompanied the co-ingestion of glucose and fructose was not associated with an increase in glucose Ra/Rd.
Somebody want to translate what Andy just said?
Most of what he says is good, and I like to try and pay attention. Even if he did say on the wattage forum that I don’t have a high enough FTP to race P/1/2 crits. Andy, I’m mailing my national medals for points race, TP, and crit back tomorrow.
Somebody want to translate what Andy just said?
I was pointing out that the increase in carbohydrate oxidation was not due to increased glucose delivery to muscle via the circulation. IOW, it either occurred “upstream” of that point (i.e., in the liver - which seems quite possible) or it was due to increased use of muscle glycogen “downstream” (which seems unlikely, albeit not impossible). In any case, what is important to recognize is that it is muscle substrate utilization that really matters in terms of performance, and in that regard the co-ingestion of glucose and fructose may not (or may) be beneficial.
Even if he did say on the wattage forum that I don’t have a high enough FTP to race P/1/2 crits. Andy, I’m mailing my national medals for points race, TP, and crit back tomorrow.
Was it you who posted recently about your 1 min power? If so, I didn’t say that your threshold power wasn’t high enough to race P/1/2, what I said was that I thought it was more likely to be limiting than your 1 min power. (An belief reinforced by your placings in the points race and crit especially.)
Marty,
I shared a house with Michael Folan from Infinit Nutrition at IMCdA 2006. He told me about this research. At the time, I was using pure-Malto (buying it in 40 lbs. bags) and flavoring with Crystal Light. Michael taught me that POWDERED Gatorade will actually use Sucrose (vice HFCS in the mixed drink). I had some success mixing pure-Malto with powdered Gatorade Drink Mix (which also served as a flavor).
For those less-inclined to mix their own, I’d recommend using Scott McMillan’s Factor-9 Infinit Blend (in the interest of honesty, I’ve previously coached with Scott and consider him a good friend).
As with anything, look to try it in training. However, I found that I could increase my calories and decrease some of my bloating by using the mix.
Regards,
Puskas
Yeah, that was a really good podcast, one of the best I’ve ever heard. Who knew that asking intelligent people about subjects about which they are passionate would make for good listening and learning?
Does anybody have any suggestions for the fructose portion of the 2/1 glu/fru mix? I’ve got the glucose covered (carbopro), but I can’t find plain fructose anywhere.
-C