Can anyone tell me the difference between Maltodextrin and Glucose (as found in Carbo Pro) in terms of long course (pre, during and post) fueling value?
Glucose is fast, usefull all the time, but gets to be burned as energy first. Maltodextrin takes a while to become fuel and should be considered useless in an event under 1-2 hours. You could use it in all three cases as your energy needs are an ongoing process.
My understanding is that with Maltodextrin, your body is more forgiving about the water requirements in order to process it.
That has been my experience anyway. I can get the Carbopro down with no problem.
If you do a search on the subject, you will find a lot of much more precise explanations.
It aint long. The main purpose is to decrease the osmolarity of what hits your stomach, so that you don’t get a stomach ache from all of the water that would be needed to equalize that osmaolariy from rushing through your mucosa into your gut. (Wow! way too long on that sentence.)
This is off the top of my head, so forgive me if not totally correct…
Yes the intestine does sense osmolality and will slow down gastic emptying when a hyperolmolar solution is dumped into it. I guess the question is how fast maltodextrin gets broken down and how long the oligosaccharides “hang out” before being absorbed. You won’t see much free glucose in the gut because the enzyme that breaks gown the oligosaccharides is located at the brush border of the intestinal cells - the resulting glucose would probably be very rapidly absorbed.
So in plain English, it would seem that if the breakdown products of maltodextrin were absorbed quickly enough then the intestine may not signal the stomach to slow down. I don’t really know how the kinetics plays out in real life though.
If we are, let’s not tell anyone… 
My experiene with the stuff supports what you said. Worked awesome in an IM and absorbed quickly (no stomach issues and plenty of juice going into the run). Also works well in shorter (1.5 to 2 hour) training rides.
Perhaps my timing is long, but it does need to “hook” up with amylase in the small intestine to be broken down into glucose. As a complex carb it certainly beats say a bowl of wheaties.
Yes, but the absorbtion of glucose is the rate-limiting step, not the enzymatic breakdown of the maltodextrin. So a maltodextrin solution is absorbed as fast as a glucose solution.
The correct proportionas of Glucose, Sodium and Potassium help turn on the Sodium-Potassium ATPase pump ( unless the name has changed) which actively pumps all three into the mucosa, with the water.
Sort of… you need sodium present in order to get glucose absorbtion but…
The Na/K ATPase is on the basolateral side of the intestinal cell, pumping Na out and K in, setting up the gradient which favors Na influx from the gut lumen. Glucose and sodium are taken in together via the sodium-dependent-hexose-transporter on the apical surface.
Well, interesting discussion here. I did all my training for years and years on Gatorade. Worked fine for me.
However, I recently purchased some Perpetuum and am using it on my long rides and runs. I notice that I don’t get as big an energy spike with Perpetuum and I don’t go as low as I would sometimes get on Gatorade. The energy curve seems to be a bit flatter. Maybe this is just perception, but I did drop 3 minutes off my 58 mile bike split the second time I used Perpetuum. 
-Robert
Check the Glycemic Index for Glucose, sucrose, maltodextrin etc. Assuming the chart is correct:
Fructose 22
Honey 58
Sucrose 64
Glucose 96
Maltodextrin 105
So according to the GI charts Maltodextrin is very slightly faster than Glucose in raising the blood sugar. Gatorade rates an 89 for reference. I haven’t tried solutions with glucose as the primary source, but I know that maltodextrin solutions work well for me. Ones high in Fructose and Sucrose (Gatorade, PowerAde) really screw up my stomach…I learned that almost 15 years ago.
I think the main claim of mfrs that use Maltodextrin is that it empties from the stomach faster than glucose and doesn’t carry as much water from the stomach in order to be digested in the intestines. Not sure if this is true or not, or whether it is good or not.
This may be a reasonable place to buy it. You can also customize your own protein drink
http://proteinfactory.com/store/default.php?cPath=22_29&osCsid=e59ba37fc862251f1b6db54cc99a7ee6
I think the main claim of mfrs that use Maltodextrin is that it empties from the stomach faster than glucose and doesn’t carry as much water from the stomach in order to be digested in the intestines
That sounds right to me.
Fructose is absorbed really slowly in the gut and therefore causes GI problems for a lot of people. A little fructose isn’t a bad idea though, as it’s taken up by a different system than glucose (and so will not compete with glucose for absorbtion)
I stand corrected, it’s been too long.
Sucrose is a glucose-sucrose disaccharide. So, when it is split the fructose takes a while to get fitted with 2 phospates so that it can be metabolized.
If I recall, the original Gatorade (by Stokely Van Kamps) had glucose (with a little additional saccharin for sweetness). When everyone got their bees in bonnets about saccharin, in the 80’s, the formula was changed. It’s tastes better, but I never found it was absorbed as quickly after that. (THis may be pure perception.) The original formula was the greatest for long tennis matches in New Orleans. I used to saturate a bath towel in warm up and one set there. After I was introduced to Gatorade in 1976, the second set was infinitely better.
I actually mix it a little lean and add salt for most of my work outs.
That’s pretty cool - I kinkd of like the idea of making a custom drink. Probably a lot cheaper too.
That’s a great help, JHC. Thank you.
As you can see, I am trying to figure out the best way to fuel for long course training and racing. My thought/goal is to go as simple as possible and some helpful forum reading, like your response, has sort of made it look like simpler is definitely achieveable with the right ingredients.
I did IMLP on water, Hammer Gel and Endurolytes, which worked well, for the most part (no gastric problems and a little behind the feed curve early on the bike) but I still qualified for Kona. All I had to do was exchange a couple of gel flasks at Special Needs and could use the water on the course. So I think that simple route will work for me, but I want to see if I can maybe I can substitute less commercial/cheaper ingredients (and not have to be buying $30 containers of potions several times a week).
I bought a 50lb bag of Maltodextrin from a grain processor and a 50lb bucket of rice syrup from a rice farm. They seem like fine substitutes (per forum input) and now I have to figure out how to use them…Research tells me that rice syrup is the same as many gels. Do you know anything about that? How about mixing Maltodextrin powder in water? I guess I can go pretty high in terms of solution density. I wonder if I can make a gel/paste with that? I think I would try to mix some Endurolyte powder into one or both, instead of having to carry/take separate pills…
Any thoughts?
There’s been a couple of threads on homemade gels, including recipes with maltodextrin and rice syrup. Do a search for “homemade gel” and you’ll see all you need.
It seems like a lot of sports drinks and gels use maltodextrin as the main ingredients (Clff Shots use rice syrup). I like the idea of making a homemade gel or drink… might start doing it myself.