T Nation

Dextrose, Malto, and Honey, Oh My!

I understand that there are varying GIs in Maltodextrin, but in dextrose it is all the same? I don’t have to worry about anything like that in Dextrose? Obviously lower GI doesn’t seem to be ideal for post workout…

I used to be taking this maltodextrin here: http://www.nutrabio.com/Products/carbomax_maltodextrin.htm Would you please take a look at that? What are your thoughts on that? Not ideal for post-workout?

I am going to be working out for muscle mass / bulking. I was thinking of buying this dextrose here: http://www.breworganic.com/index.asp?PageAction=VIEWPROD&ProdID=1114 That’s OK for post-workout? I think it’s more pricey than regular dextrose but that’s because it’s not GMO and it’s organic whereas all the other cheap dextrose is from GMO corn and organic, and from what I know about GMO it isn’t that great for the body especially long term…so was thinking to “go green” with this one, lol. we’ll see.

Also, what do you think about their maltodextrin: http://www.breworganic.com/index.asp?PageAction=VIEWPROD&ProdID=1012 How can I know if this is the one that is ideal for post-workout? It sounds like theirs is from corn. Are maltodextrin from corn the one that is High GI and good for post workout?

I heard combining malto and dextrose 50/50 theoretically gives you an edge, and plus it cuts down the sweetness and makes the PWO shake more bearable. But malto seems unpredictable as far as GI goes. Anyone know about my question regarding if malto is from corn then that means high GI? I know they have malto from potato, rice, tapioca, etc. and doesn’t always say source or processing method.

Any recommended supps? I read on the forums someone mentioned “Surge” what exactly is that? url anyone?

Also, what about honey? There’s some info on the web about honey being a more better alternative to malto and dextrose…at least a good post workout drink. Is honey low Gi or High GI? Lots of nutrients in honey compared to nutritionless dextrose and malto.

Thanks,

JM

Honey is slightly more than half fructose, which is much too much for a post-workout drink as muscle cannot utilize fructose.

I think a PWD should at the least be high in glucose or be all glucose in terms of carbs. If all glucose, though, there should be a refeed after one hour with complex carbs and protein, whereas if there was a lot of maltodextrin perhaps one can go 2 hours.

[quote]Bill Roberts wrote:
Honey is slightly more than half fructose, which is much too much for a post-workout drink as muscle cannot utilize fructose.

I think a PWD should at the least be high in glucose or be all glucose in terms of carbs. If all glucose, though, there should be a refeed after one hour with complex carbs and protein, whereas if there was a lot of maltodextrin perhaps one can go 2 hours.[/quote]

Bill, just a question on Honey. What are your thoughts on the differences between Organic Raw Honey and the stuff you get in the grocery store?

Malinda

There would be no significant if any difference in amounts of fructose and glucose.

I suppose it is possible that with non-organic honey the bees might collect pollen that had had pesticide sprayed on it whereas perhaps with organic honey (I don’t know) all the flowers in the area are organically grown and thus don’t have pesticide.

As to whether pesticide in the pollen actually makes it into the honey, I have no idea.

So far as claims of there being an advantage to being unprocessed (all that is involved in the processing is a minor amount of heat, I believe about 77 degrees C, and filtration) well here are example claims:

[i]Honey that’s truly raw - not exposed to more than 118 degrees Fahrenheit - contains the following nutrients that can nourish your cells and keep you healthy:

A number of flavonoids, which are antioxidants that can help keep your cardiovascular system healthy and help prevent damage caused by excessive amounts of free radicals

Amino acids (building blocks of protein in your body)

Enzymes

Trace amounts of calcium, magnesium, iron, zinc, potassium, and a number of other minerals

Healthy, natural sugars (fructose and glucose) that can help create glycogen stores in your liver and muscles, and provide a source of energy to your cells[/i]

This makes utterly no sense, as flavonoids are not going to damaged by brief exposure to 77 C or anything like that; amino acids are not; the minerals mentioned are not; and the fructose and glucose are not.

The only thing there could even vaguely be a point on would be enzymes, but I would really expect stomach acids and one’s own digestive enzymes are going to do far more to break down the enzymes in any case than the heat processing will.

Besides this, if any enzyme is absorbed intact – enyzmes are proteins – I don’t know what it is. It is true that bromelain has systemic beneficial effects so something beneficial is absorbed from it, but I know of no evidence that intact bromelain is absorbed. Actually, given how indiscriminately and rapidly bromelain itself hydrolyzes proteins, it seems to me that intact bromelain is one of the last things one would want in the blood. (Try adding some into a raw cubed steak at room temperature and wait no great length of time. You’ll fairly promptly have absolute mush. It’s incredibly destructive to muscle tissue, which is what beef is for the most part. So I don’t think bromelain is an exception to what seems to me a rule that enzymes, being proteins, aren’t absorbed intact.)

There are some things where organic really is different, but as guesswork I really doubt honey is one of them.

Not for use PWO, but white Hawaiian honey (sold in those little jars from Whole Foods) is to die for. Has a VERY buttery flavor.

Bill,

Honey has been used by many tribal people in treating digestion issues and, in the Amazon, in treating symptoms induced by the venom of salamanders (or I think frogs or both). Interesting.

Honey is a fascinating food. I think the only food that won’t spoil.

I wish Berardi would write more about foods and their use/impact on ancient cultures. Black cumin, for instance, is only recently being revisited for some interesting properties it has. The Prophet Mohammad once said it could ‘cure everything but death itself.’

The principal reason honey doesn’t spoil is that its water content is so low that bacteria are dehydrated by it.

Add water and bacteria will grow in it exceedingly easily and happily. (To the extent that bacteria can be happy.)

That is not to disagree that it can be useful topically for wound healing and treatment of infections, it can. But the principal reason is not what is commonly thought.

Thanks for the information Bill. I know that the taste is very much different between the two. And I have a big downfall for peanut butter and honey mixed…I know not a good diet food, but hey a girls gotta indulge once in a while…

Yes, I should have included that the taste changes. I was thinking only nutritionally. You’re completely right of course.

My grandfather has an apiary and the flavour of the honey differs from year to year. Mostly, depending on the type of spring/summer we have and what is growing in the area. Basically, the taste varies based on the bee’s diet.

And white honey someone was talking about might be cream honey. Kind of cool that you can make cream honey by “seeding” a barrel of regular honey with a tablespoon of cream honey and it slowly turns the whole thing to creamed.

Hi Bill,

Thanks for the reply.

I’ve heard the reason fructose isn’t that great is because it gets converted into the liver… but doesn’t it get converted into glucose/glycogen, so why is the consensus that after liver glycogen stores are filled the rest of the glucose/glycogen turns to fat? If there is a need i.e. depleted muscle glycogen, won’t the body utilize that glucose?

I mean in the end, doesn’t everything (through different mechanisms) get converted to glucose? And ofcourse, excess energy/calories is stored as fat… but when there’s a need, it would only make sense that the body is smart enough to use it. So please help me understand this…theory? Is this just theory or fact and if fact, based on what? studies, etc?

Also, anyone know about maltodextrin GI? a lot of people recommend maltodextrin for postworkout but I’ve read that maltodextrin actually can be low Gi! meaning low insulin response right? And that’s bad then? Because we want a high insulin rise. For instance, this is the one that i had used in the past: http://www.nutrabio.com/Products/carbomax_maltodextrin.htm and it is described as so:

“CarboMax is a pure source of complex carbohydrates made from LCPF-50 (long-chain polymetric fraction) maltodextrin. CarboMax contains complex glucose polymers that are metabolized at a slow, steady rate making CarboMax the smart choice for athletes who want to increase muscle endurance and mass without the complications of simple sugars.”

Is this a low Gi maltodextrin?

Thanks,

JM

[quote]justmarvin wrote:
“CarboMax is a pure source of complex carbohydrates made from LCPF-50 (long-chain polymetric fraction) maltodextrin. CarboMax contains complex glucose polymers that are metabolized at a slow, steady rate making CarboMax the smart choice for athletes who want to increase muscle endurance and mass without the complications of simple sugars.”

Is this a low Gi maltodextrin?
[/quote]

No, it’s called marketing nonsense.

Um… you probably aren’t aware that maltodextrin has different Dextrose Equivalent. I meant to say “DE” not GI, but it seems that DE and GI should go hand in hand… a low dextrose equivalent rating on maltodextrin should be low GI it would seem. So via that description above, I’d say that’s probably a low DE maltodextrin.

People take maltodextrin for postworkout assuming that it is about the same as Dextrose. But again there different Dextrose Equivalent (or DE) ratings, and as the description to the product I linked to, that sounds like a low DE… “metabolized at a slow steady rate” Thus, this doesn’t seem all too great for a post workout carb, any thoughts on that?

JM

[quote]justmarvin wrote:
Hi Bill,

Thanks for the reply.

I’ve heard the reason fructose isn’t that great is because it gets converted into the liver… but doesn’t it get converted into glucose/glycogen, so why is the consensus that after liver glycogen stores are filled the rest of the glucose/glycogen turns to fat? If there is a need i.e. depleted muscle glycogen, won’t the body utilize that glucose?[/quote]

It’s not per se that it’s utilized by the liver that is such a reason not to use it post-workout, but the fact that it is not usable by muscle, and the main point of post workout carbs is to provide them to muscle.

As for being used by the liver, if what occurs is just replenishing of liver glycogen stores that’s fine.

Your suggestion that if liver glycogen is already fully restored then still-further glucose would still get converted to glycogen and simultaneously other glycogen would be hydrolyzed to yield glucose would be a nice mechanism fot the liver to effectively convert fructose to glucose supplied to the bloodstream on the fly, but at least so far as I was taught in biochemistry and anything I’ve ever read on it since, this is not what happens, but instead the liver uses the fructose to produce fat.

No, that isn’t the case at all. For example fats are never converted to glucose. Some amino acids can be, others are not. They can be burned without ever being converted to glucose, particularly the BCAA’s. Fructose is also not necessarily converted to glucose.

I believe it to be very thoroughly demonstrated fact but it’s been many years since I could have cited a specific study showing it. If interested you could probably find something yourself using Google Scholar or possibly find a chapter of a biochemistry text covering the relevant metabolism online with regular Google. It might take half an hour or more to find it though, I have no idea as I haven’t done it, just by way of warning that kind of thing can take a little while in many cases. (Sometimes many hours but probably not for this.)

[quote]Bill Roberts wrote:
It’s not per se that it’s utilized by the liver that is such a reason not to use it post-workout, but the fact that it is not usable by muscle, and the main point of post workout carbs is to provide them to muscle.

As for being used by the liver, if what occurs is just replenishing of liver glycogen stores that’s fine.[/quote]

Hi Bill, can you please explain a little further why fructose can’t be used by the muscles since fructose does get converted to glucose in the liver. Thanks, I appreciate your replies, and I’m wanting to understand this a bit further.

[quote]Your suggestion that if liver glycogen is already fully restored then still-further glucose would still get converted to glycogen and simultaneously other glycogen would be hydrolyzed to yield glucose would be a nice mechanism fot the liver to effectively convert fructose to glucose supplied to the bloodstream on the fly,

But at least so far as I was taught in biochemistry and anything I’ve ever read on it since, this is not what happens, but instead the liver uses the fructose to produce fat.[/quote]

I did a little bit more research, and I read that fructose gets converted to glucose in the liver. The glucose is then released to the bloodstream for use by the body. And any excess glucose gets converted to fat (no big surprise there).

So this seems to suggest that once in the bloodstream the glucose should be able to refill muscle glycogen…because the body has a need for it.

What about gluconeogenesis? Isn’t that the process when fats or protein get converted to glucose? Pointing out that fat can convert to glucose. Of course carbs are the preferred source, but in the absence of carbs, the body uses what it has, thus carbs proteins and fats do seem to be convertible.

And, you said fructose is not necessarily converted to glucose, then what is it converted to? From what I read it is converted to glucose and then the excess glucose is converted to fat when that glucose is not needed & not fructose converted directly to fat.

[quote]I believe it to be very thoroughly demonstrated fact but it’s been many years since I could have cited a specific study showing it. If interested you could probably find something yourself using Google Scholar or possibly find a chapter of a biochemistry text covering the relevant metabolism online with regular Google.

It might take half an hour or more to find it though, I have no idea as I haven’t done it, just by way of warning that kind of thing can take a little while in many cases. (Sometimes many hours but probably not for this.)
[/quote]

I did a search on google, and it seemed to confirm that fructose does get converted to glucose and released in the bloodstream. Anyway, I saw this interesting study and wanted to know what you thought, sort of related, sort of…

"Fructose and glucose ingestion and muscle glycogen use during submaximal exercise

L. Levine, W. J. Evans, B. S. Cadarette, E. C. Fisher and B. A. Bullen

Substrate utilization after fructose, glucose, or water ingestion was examined in four male and four female subjects during three treadmill runs at approximately 75% of maximal O2 uptake. Each test was preceded by three days of a carbohydrate-rich diet.

The runs were 30 min long and were spaced at least 1 wk apart. Exercise began 45 min after ingestion of 300 ml of randomly assigned 75 g fructose (F), 75 g glucose (G), or control ©. Muscle glycogen depletion determined by pre- and postexercise biopsies (gastrocnemius muscle) was significantly (P less than 0.05) less during the F trial than during C or G.

Venous blood samples revealed a significant increase in serum glucose (P less than 0.05) and insulin (P less than 0.01) within 45 min after the G drink, followed by a decrease (P less than 0.05) in serum glucose during the first 15 min of exercise, changes not observed in the C or F trials.

Respiratory exchange ratio was higher (P less than 0.05) during the G than C or F trials for the first 5 min of exercise and lower (P less than 0.05) during the C trial compared with G or F for the last 15 min of exercise.

These data suggest that fructose ingested before 30 min of submaximal exercise maintains stable blood glucose and insulin concentrations, which may lead to the observed sparing of muscle glycogen."

Now this isn’t post workout, but it’s interesting still and I would think a bit unexpected. Why do you think fructose would provide more stable blood glucose? I always thought complex carbs are more stable.

JM

[quote]justmarvin wrote:
Bill Roberts wrote:
It’s not per se that it’s utilized by the liver that is such a reason not to use it post-workout, but the fact that it is not usable by muscle, and the main point of post workout carbs is to provide them to muscle.

As for being used by the liver, if what occurs is just replenishing of liver glycogen stores that’s fine.

Hi Bill, can you please explain a little further why fructose can’t be used by the muscles since fructose does get converted to glucose in the liver. Thanks, I appreciate your replies, and I’m wanting to understand this a bit further.[/quote]

It isn’t fructose the muscles are using in your example, it’s glucose. So there was nothing wrong with my statement when read as intended. There was no intention of an implication that the muscles can’t use what was once ever fructose someplace else in the body but is glucose now when reaching the muscle.

[quote]I did a little bit more research, and I read that fructose gets converted to glucose in the liver. The glucose is then released to the bloodstream for use by the body. And any excess glucose gets converted to fat (no big surprise there).

So this seems to suggest that once in the bloodstream the glucose should be able to refill muscle glycogen…because the body has a need for it.[/quote]

You’re assuming that this is happening promptly enough on the fly to support the PWO usage, which is what was being discussed. If you were right then wouldn’t blood glucose rise and insulin rise just as much from fructose intake as from glucose intake?

But that is proven to be not remotely the case. Blood glucose does not rise with fructose intake anywhere near like what it does with glucose intake.

So PWO fructose does not generate the blood glucose levels that glucose intake does, and since the muscles need glucose not fructose which they themselves cannot use, fructose does not meet the intended purpose.

What?!?

No, fat cannot.

As I said, some amino acids can, some cannot.

No, not fats and not all amino acids.

There is more you can read on it that would be of value and may help explain this. One of the first hits that turns up on Google is http://www.nutritionandmetabolism.com/content/2/1/5

which is pretty good.

Not as fast as it’s intended to deliver glucose in the PWO situation.

The fact that blood glucose levels do not rise rapidly nor is there much insulin rise from fructose, but there is with glucose, demonstrates that your on-the-fly-conversion they’re-equivalent interpretation cannot be right.

[quote] Anyway, I saw this interesting study and wanted to know what you thought, sort of related, sort of…

"Fructose and glucose ingestion and muscle glycogen use during submaximal exercise

L. Levine, W. J. Evans, B. S. Cadarette, E. C. Fisher and B. A. Bullen

Substrate utilization after fructose, glucose, or water ingestion was examined in four male and four female subjects during three treadmill runs at approximately 75% of maximal O2 uptake. Each test was preceded by three days of a carbohydrate-rich diet.

The runs were 30 min long and were spaced at least 1 wk apart. Exercise began 45 min after ingestion of 300 ml of randomly assigned 75 g fructose (F), 75 g glucose (G), or control ©. Muscle glycogen depletion determined by pre- and postexercise biopsies (gastrocnemius muscle) was significantly (P less than 0.05) less during the F trial than during C or G.

Venous blood samples revealed a significant increase in serum glucose (P less than 0.05) and insulin (P less than 0.01) within 45 min after the G drink, followed by a decrease (P less than 0.05) in serum glucose during the first 15 min of exercise, changes not observed in the C or F trials.

Respiratory exchange ratio was higher (P less than 0.05) during the G than C or F trials for the first 5 min of exercise and lower (P less than 0.05) during the C trial compared with G or F for the last 15 min of exercise.

These data suggest that fructose ingested before 30 min of submaximal exercise maintains stable blood glucose and insulin concentrations, which may lead to the observed sparing of muscle glycogen."

Now this isn’t post workout, but it’s interesting still and I would think a bit unexpected. Why do you think fructose would provide more stable blood glucose? I always thought complex carbs are more stable.[/quote]

I would think the reason for more stability is because insulin production is not triggered by the fructose intake, but only by glucose the fairly-steady-rate conversion process in the liver, which is not going to yield the spikiness (scientific term there) of glucose absorption from the GI tract.

Good find on that study. I had read something similar a while back but had essentially completely forgotten it (where the only thing that brings it back is seeing the same kind of thing, it couldn’t come back from conscious recall) till you posted this, and it’s a worthwhile thing to know.

It’s not a trivial workrate that’s being supported either.

Now, I would not assume that the workrate is being supported entirely or even necessarly mostly by glucose provided via conversion of the fructose. Very likely triglycerides were also produced, perhaps predominantly, and the muscles can burn fatty acids from triglycerides, especially with regard to aerobic exercise such as this.

Burning fatty acids spares muscle glycogen. So without their having measured triglycerides, I wouldn’t assume that the conversion rate to glucose was at as high a caloric rate as the workload was.

The abstract seems unclear on the respiratory exhange ratio. If nothing but carbs were burned in the body, the ratio would be 1.0. If nothing but fat, 0.7.

It states plainly that in the first 5 minutes, RER was lower in the fructose group than in the glucose group, meaning that they weren’t burning as much glucose as the glucose group (no surprise) and instead were burning more fatty acids.

However it doesn’t discuss differences between the glucose and fructose groups at other time points. It may be that a difference in the average was seen but the noise (random variation) was too much to be able to report a figure.

[quote]justmarvin wrote:
Um… you probably aren’t aware that maltodextrin has different Dextrose Equivalent. I meant to say “DE” not GI, but it seems that DE and GI should go hand in hand…

a low dextrose equivalent rating on maltodextrin should be low GI it would seem. So via that description above, I’d say that’s probably a low DE maltodextrin.

People take maltodextrin for postworkout assuming that it is about the same as Dextrose. But again there different Dextrose Equivalent (or DE) ratings, and as the description to the product I linked to, that sounds like a low DE… “metabolized at a slow steady rate” Thus, this doesn’t seem all too great for a post workout carb, any thoughts on that?

JM
[/quote]

From what I understand, maltodextrin is broken down so quickly that is is just a tad bit slower to be digested than plain dextrose. Maybe a malto of 50DE is broken down slower than one of 20DE, but I believe the end result is negligable. Your original maltodextrin you were using was probably fine.

I buy both malto and dextrose and mix them 50/50 in my drink because I buy them at the same place and it is easy for me. I wouldn’t freak out if I had to choose one or the other though.

Also, I know this is another topic/thread in itself, but where is ANY evidence showing GMO are bad for people AT ALL? No offense, but I’d be willing to bet ‘what you know about GMO’ isn’t much.

[quote]ktennies wrote:
From what I understand, maltodextrin is broken down so quickly that is is just a tad bit slower to be digested than plain dextrose. Maybe a malto of 50DE is broken down slower than one of 20DE, but I believe the end result is negligable. Your original maltodextrin you were using was probably fine.
[/quote]

Interesting. Can anyone confirm or provide a link to more info on “DE”?

None taken, but no offense, but you’re being offensively presumptuous. :wink: The topic of GMO foods is one worth looking into in my oppinion, and fyi - one that i’ve researched quite a bit about.

JM

[quote]Bill Roberts wrote:
It isn’t fructose the muscles are using in your example, it’s glucose. So there was nothing wrong with my statement when read as intended. There was no intention of an implication that the muscles can’t use what was once ever fructose someplace else in the body but is glucose now when reaching the muscle.[/quote]

Ok, so what I’ve been wondering was…once fructose is converted to glucose the body should use it to replenish muscle glycogen stores. Sure it won’t be as fast as straight complex carbs like dextrose which goes to the bloodstream right away, and sure that may give an edge to a PWO shake, but even so, why do people say something towards the line of “oh no that’s too much fructose, it won’t be used to replenish muscle glycogen, it will be turned to fat.” And isn’t that what your statement here implies as you said:

“Your suggestion that if liver glycogen is already fully restored then still-further glucose would still get converted to glycogen and simultaneously other glycogen would be hydrolyzed to yield glucose would be a nice mechanism fot the liver to effectively convert fructose to glucose supplied to the bloodstream on the fly, but at least so far as I was taught in biochemistry and anything I’ve ever read on it since, this is not what happens, but instead the liver uses the fructose to produce fat.”

But yet you also said “There was no intention of an implication that the muscles can’t use what was once ever fructose someplace else in the body but is glucose now when reaching the muscle.” It sounds like a contradiction but maybe i’m not understanding right, would you please clarify? thanks.

It sounds like that your point is that fructose to glucose conversion is not done “on the fly,” and by “on the fly” do you mean at an accelerated rate like how dextrose/glucose goes straight to the bloodstream? And sure it has to go through an extra step in the liver for conversion, but how much longer will it take anyway? Ultimately, it gets converted to glucose. And as far as that “golden window” of opportunity for post workout feeding, an hour is ideal yeah, but i’ve read other things that said the body is in that “golden window” state for a lot, lot longer. And what about the bodybuilders of the past who mainly would eat solid food post workout (like pasta, steak, etc) which has to go through longer digestion/processing as compared to the “on the fly” liquid glucose carbs such as dextrose. Yet those were what helped sculpt the Olympian pros. So in regards to fructose not being glucose-available “on the fly,” why does it have a bad rap as “not useable for the muscles - it will convert to fat.” Again, I’m still not clear why the energy from fructose would turn to fat unless there is no need for glucose i.e. excess, but the body will have a need because muscle glycogen is depleted, on top of that you have an accelerated metabolism due to exercise, so fructose should be acceptable PostWorkout and replenish muscle glycogen without worry of getting converted to fat it seems to me… Your thoughts?

[quote]
Justmarvin:
I did a little bit more research, and I read that fructose gets converted to glucose in the liver. The glucose is then released to the bloodstream for use by the body. And any excess glucose gets converted to fat (no big surprise there).

So this seems to suggest that once in the bloodstream the glucose should be able to refill muscle glycogen…because the body has a need for it.[/quote]

[quote]Bill Roberts:
You’re assuming that this is happening promptly enough on the fly to support the PWO usage, which is what was being discussed. If you were right then wouldn’t blood glucose rise and insulin rise just as much from fructose intake as from glucose intake?

But that is proven to be not remotely the case. Blood glucose does not rise with fructose intake anywhere near like what it does with glucose intake.[/quote]

Does it have to happen “on the fly” (per my definition/understanding that i stated above) VS. fructose having to be converted to glucose in the liver… well, after conversion, again, it seems we both agree that the body should still be able to use it.

It sounds you are bringing up an issue of blood glucose rise, and from what I understand this is determined by the GI of foods, right? You said that Blood glucose rise is not anywhere like what glucose would give, but what about the higher fructose foods, like carrots? Ofcourse we have to take out the fiber in the picture here, so “carrot juice” is what I’m thinking. This is a high GI food over a hundred+. And maybe you can explain the whole issue of GI in relation to this. How I picture GI, in layman’s terms, is simply like this: you can picture a bathtub, and the pressure/speed of the water running is the “GI,” water being blood glucose, and the size of the bathtub is in relation to the body’s needs for the glucose/energy, so when your exercising the bathtub is bigger and it could hold more water, and so high GI foods are OK in that instance, and if your body doesn’t need the energy, then the bathtub is smaller, and if you overflow this bathtub, well then there are problems… obviously, excess energy being converted to fat is one of those problems. Ok, my point is this: sure the food in question may be a lower GI/blood glucose response i.e. the faucet is running slower, but the point is…the faucet is still running and the bathtub will still get filled up. So, again, I still don’t get why people don’t see fructose as being able to be a food source that will replenish muscle glycogen since fructose gets converted to glucose and glucose to liver and muscle glycogen.

I also did a brief google search and found this:

“Bryan Haycock:
There has been some controversy about which type of carbohydrate is best for post exercise glycogen replenishment. Some argue that simple sugars such as dextrose are best after exercise. Others say that drinks with glucose polymers are best. Still others say that there is no need to buy fancy sports drinks and that simply eating a meal high in carbohydrates such as pasta or rice is sufficient. Studies have shown no difference between different types of carbohydrates eaten post exercise and the rate of glycogen replenishment as long as sufficient quantities of carbohydrate are consumed (Burke 1997). Even when the post exercise meal contains other macronutrients such as proteins and fats, the rate of glycogen replenishment is not hindered, given there is sufficient carbohydrate in the meal as well. These studies tell us that the rate-limiting step in glycogen replenishment after exercise is not in digestion or the glycemic index of a given source of carbohydrate. Over a 24 hour period it is the total amount of carbohydrate consumed that is important.

[quote]Bill Roberts:
No, fat cannot [convert to glucose][/quote]

I’m not too sure myself, but if you google this, the defenition for gluconeogenesis is basically the body’s ability to convert protein or fat to glucose. Maybe you can check this and see.

[quote]
Justmarvin:
And, you said fructose is not necessarily converted to glucose, then what is it converted to? From what I read it is converted to glucose and then the excess glucose is converted to fat when that glucose is not needed & not fructose converted directly to fat.[/quote]

Thanks for that link. But, since you read it, if you can please summarize it’s findings in relation to my question that I asked?

[quote]
The fact that blood glucose levels do not rise rapidly nor is there much insulin rise from fructose, but there is with glucose, demonstrates that your on-the-fly-conversion they’re-equivalent interpretation cannot be right.[/quote]

That is not my interpretation, nor is it my original question. I was not saying that they get converted in equal rates, obviously not. One is direct to the bloodstream, and the other is going through conversion in the liver. But, once again, I was wondering why a lot of people in the bodybuilding circle believe stuff like “No - that’s fructose, it’s not going to be used as muscle glycogen, it will turn to fat.”

[quote]
I would think the reason for more stability is because insulin production is not triggered by the fructose intake, but only by glucose the fairly-steady-rate conversion process in the liver, which is not going to yield the spikiness (scientific term there) of glucose absorption from the GI tract.

Now, I would not assume that the workrate is being supported entirely or even necessarly mostly by glucose provided via conversion of the fructose. Very likely triglycerides were also produced, perhaps predominantly, and the muscles can burn fatty acids from triglycerides, especially with regard to aerobic exercise such as this.

Burning fatty acids spares muscle glycogen. So without their having measured triglycerides, I wouldn’t assume that the conversion rate to glucose was at as high a caloric rate as the workload was.[/quote]

Are you assuming maybe that the test subjects were burning body fat? Or that the fructose was converted to fat and that was available to use as energy? Because if the latter then i would ask why the body would do that since glucose is the preferred fuel compared to fat. Also, 75% is a good enough intensity to start using carbs, and from what I understand, it’s unlikely to use fat stores as the first choice of energy source after consuming carbs since the body’s preferred source of fuel is carbs not fat unless in a fasted state cardio and/or at low enough intensity…

We might also consider the rate at which glucose is released. Perhaps a more steady rate of glucose being released into the body may be the factor in the case of this study.

Also, have you read the honey study? I’ve read it before, but did a quick search and only found a summary so far:

"Nine competitive cyclists received one of three supplements in gel form per week, over a three week period: honey, glucose or a flavored, calorie-free placebo. The endurance test conducted each week was a 64 km (40 miles) time trial on each subject�??s racing bicycle, fitted to a calibrated, computerized race simulator. The cyclists received 15 grams of carbohydrate in gel form along with 250 ml of water prior to and every 16 km during the time trials.

Both the glucose and honey produced a statistically significant reduction in the time to finish, and a significant increase in the athletes’ average power. The results of the study indicate that honey is an effective and affordable alternative carbohydrate source for endurance athletes."

Basically, this to me seems to suggest that honey (which is about significantly half fructose composition) was able to sustain the energy needed for the cyclist, an in fact helped them finish significantly faster, and since the best source for fueling intense activities is glucose, it looks to be that glucose is being the primary fuel here, and here we can see that steady-rate, lower GI, and it’s actually a benefit.

[quote]The abstract seems unclear on the respiratory exhange ratio. If nothing but carbs were burned in the body, the ratio would be 1.0. If nothing but fat, 0.7.

It states plainly that in the first 5 minutes, RER was lower in the fructose group than in the glucose group, meaning that they weren’t burning as much glucose as the glucose group (no surprise) and instead were burning more fatty acids.

However it doesn’t discuss differences between the glucose and fructose groups at other time points. It may be that a difference in the average was seen but the noise (random variation) was too much to be able to report a figure. [/quote]

I guess we can’t really say if they were burning fat exactly since we don’t know the ratio. But would not the ratio somewhat follow the intensity? Meaning in the case of the endurance cycling trials, wouldn’t that be higher intensity and thus requiring a higher ratio i.e. demand for carbs as fuel.

So, perhaps Fructose isn’t as bad as people make it out to be as far as for post-workout, not to mention pre-workout as those two studies seem to suggest.

JM

[quote]justmarvin wrote:

But yet you also said “There was no intention of an implication that the muscles can’t use what was once ever fructose someplace else in the body but is glucose now when reaching the muscle.” It sounds like a contradiction but maybe i’m not understanding right, would you please clarify? thanks.[/quote]

I said the muscles can’t use fructose. They use glucose (in terms of what sugar they use.)

You replied that well they can use fructose because the liver can convert fructose to glucose.

I replied Well they are using glucose then, aren’t they, not fructose, they themselves can’t use fructose. By the way, generally the glucose that had been fructose spends considerable time stored as glycogen before being released as glucose, rather than being promptly delivered.

There was no reason for you to take my statement as supposedly now supporting any belief that consuming fructose results in rapid delivery of similar or large amounts of glucose to the bloodstream relevant to the purposes of a a PWO drink, which is the context we’re talking about. It does not. But instead you post that supposedly I’m contradicting myself.

Or, on the I think mistaken assumption that you were asking questions to try to learn, I explain that fats cannot convert to glucose. You immediately (wrongly and for no valid reason) argue back that fats can convert to glucose. What value was there, to you, in my having provided the information? None, clearly, as it seems the reasons you are asking these things are completed unrelated to wanting to learn the answer. I give you correct information on this and other points and you act precisely as if I did not say it (unless using what I said to play a word game.)

I just don’t know where this is getting.

I’ve explained very adequately I think and as well gave you a link to a quite good article which should answer all your questions.

I’m not trying to be short or dismissive, it’s just that there is no point in being way repetitious particularly when clear statements are being argued with and by means of word play made to be supposedly wrong, e.g., arguing that muscle is able to use fructose contrary to my statement, when in fact it still is glucose that they are using (or fatty acids derived from fructose metabolism, to be more complete.)

You can make that “wrong” if you want on your argument that they are able to use what once was fructose but now it not, or say I am contradicting myself, but really dealing with that is just not the kind of thing I want to do.

If you want to learn these things instead of wanting to convince yourself you’re winning an argument, go read the link I provided last post. It will explain to you what I said (as biochemistry hasn’t changed in such basic regards, it’s all still true) and there is even more good information beyond what I said. You don’t need more posts from me; the ones already written did no good.

[quote]justmarvin wrote:

So, perhaps Fructose isn’t as bad as people make it out to be as far as for post-workout, not to mention pre-workout as those two studies seem to suggest.

JM
[/quote]

I dare say there is nothing bad about it, but the whole point of post workout nutrition is to get the carbs, protein etc into your muscles as quick as possible so you can start the recovery process ASAP. Combination of dextrose glucose and a glucose polymer maltodextrin has a synergistic effect of creating an insulin response but also having a high rate of osmosis, kick starting the recovery far quicker than fructose ever could.