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Glycemic index of gels--should I care?
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I've been trying different stuff for my long runs including Maltodextrin and this week brown rice syrup. It all seemed about the same level of grossness to me. I was reading this tidbit today

Most studies have shown that glucose and Maltodextrin can be absorbed and metabolized at up to 1.0 grams/minute, while Fructose is absorbed and metabolized at up to 0.6 grams/minute[3]. Combining Fructose with glucose/Maltodextrin can result in the metabolism of up to 1.75 grams/minute[4].

So, if I add some fructose to the maltodextrin and increase the absorption rate, is this a good thing?
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Re: Glycemic index of gels--should I care? [jroden] [ In reply to ]
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If you believe Asker Jeukendrup's work, a 2:1 ratio of glucose:fructose (found in gels such as Gu and Powerbar) improve performance over plain glucose/maltodextrin.

I, personally, (and many others I know) do not stomach fructose well. But if I could, I'd definitely use a 2:1 ratio gel.
Last edited by: Nick B: Feb 13, 16 15:21
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Re: Glycemic index of gels--should I care? [Nick B] [ In reply to ]
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isn't the GU Maltodextrin? I have never tried fructose before, I ordered a little to see how I like it. The brown rice syrup was kind of sweet and nauseating. What's glucose, something you can just buy in bulk?

So I read further and find this:

Sucrose (Sugar) is half glucose and half fructose joined together, but these components are split as part of digestion. The word 'sugar' can be used to mean any type of sugar, but in general use it refers to Sucrose. Sometimes manufacturers try to conceal sugar in the ingredients by referring to it as 'evaporated cane juice'

So why not just use plain old sugar?
Last edited by: jroden: Feb 13, 16 15:28
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Re: Glycemic index of gels--should I care? [jroden] [ In reply to ]
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jroden wrote:


So why not just use plain old sugar?


It's too inexpensive for triathletes;)

On a serious side, by using maltodextrin you can create a drink or gel with a lower osmolarity and therefor easier to absorb product for equal calories of CHO. A 3:1 ratio of maltodextri to fructose works nicely and is easier for most to tolerate.

Hugh


Genetics load the gun, lifestyle pulls the trigger.
Last edited by: sciguy: Feb 13, 16 16:27
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Re: Glycemic index of gels--should I care? [jroden] [ In reply to ]
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Malto cuz osmolarity
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Re: Glycemic index of gels--should I care? [eggplantOG] [ In reply to ]
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eggplantOG wrote:
Malto cuz osmolarity

Your big words are no match for my use of the Google. So, that means it's better absorbed?
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Re: Glycemic index of gels--should I care? [jroden] [ In reply to ]
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jroden wrote:
eggplantOG wrote:
Malto cuz osmolarity


Your big words are no match for my use of the Google. So, that means it's better absorbed?

Better stomach emptying, less likely to get you the backed up stomach that plagues is in iron distance and even more often half iron distance racing. So yes, better absorbed in the general sense but specifically better gastric emptying.
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Re: Glycemic index of gels--should I care? [jroden] [ In reply to ]
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I like gummy bears and jelly beans :p
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Re: Glycemic index of gels--should I care? [Kevin in MD] [ In reply to ]
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Kevin in MD wrote:
jroden wrote:
eggplantOG wrote:
Malto cuz osmolarity


Your big words are no match for my use of the Google. So, that means it's better absorbed?

Better stomach emptying, less likely to get you the backed up stomach that plagues is in iron distance and even more often half iron distance racing. So yes, better absorbed in the general sense but specifically better gastric emptying.

http://www.ncbi.nlm.nih.gov/pubmed/8577020
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Re: Glycemic index of gels--should I care? [jroden] [ In reply to ]
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I think the answer isn't as straight forward as we would like it to be, glycemic index is handy to know but I think we also need to factor in glycemic load and then find a combination that allows for quick take up and then has some staying power so we don't suffer throw a sugar fueled energy roller coaster.
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Re: Glycemic index of gels--should I care? [jroden] [ In reply to ]
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osmolarity probably has a lot more to do with what your gut can stand than glycemic index. The above-mentioned sugar combinations deal with how different sugars are absorbed and where they go initially--liver, straight into the blood, etc. In theory maltodextrin has lower osmolarity, but it's got a high glycemic index.

If I recall, Allen Lim thinks that most of our calories should come from solid food. But, how do you eat and swallow them while in aero position and where do you store them on the bike? He likes rice cakes, last I read.

_________________
Dick

Take everything I say with a grain of salt. I know nothing.
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