Fructose vs Other Carbs

[Riker29]

Guys, in many diet plans there are of course guidelines as to how much carbs, fats, proteins, etc.

However when considering carbs, it seems that fructose is singled out in some ways, as to be "different" as to when/where it is best (if ever) to consume it (or not).

What makes Fructose different from other carbs?

Can anyone explain this, or maybe point to a resource which discusses the different carb types, and their various effects?

 

[Silent Method]

Fructose has a very low GI, an anomoly among sugars. Also, it acts to restore liver glycogen very quickly. The fact that it does this makes it a good addition to post-workout nutrition.

 

[Riker29]

But does it have any special characteristics in terms of like ..... being converted to fat ....changing the effectiveness of a low carb diet (or not), bringing someone out of ketosis, etc

 

[Riker29]

bump

 

[georgie24]

good question bro. soooo many contradicting opinions around here it make it hard too weed out the crap

 

[Riker29]

Yeah, I am still trying to figure out all the different types of carbs, when it is best to take any, or NOT to, which are less harmful, etc.

It just seems that fructose acts or is treated differently when most people talk about diets and such, I just want a better explanation as to why.

 

[monkeyballs]

Don't know if this helps...but here is some basic science. Glucose broken down into two simple sugars, sucrose, and fructose. These are the most basic forms of simple sugars used by the human body. Each form of the simple sugars is used by the body in the same way, and therefore it can be said that Fructose is no different for the body than Sucrose. Fructose is far more common than Sucrose in today's foods because of Corn Syrup. Consuming Fructose after a workout would be no different for the body than consuming a Coke (minus the carbonation). Whether or not it is beneficial to consume fructose after a workout...I have no idea, and people here will tell you a hundred different post-workout cocktails that may or may not have fructose. It's up to you.

 

[tury]

well from the reading's I have done this is what I gathered, no I am not saying this is right but this was my conclusion. You only take high GI carbs after your workout to boost insulin levels and replesnish the muscle with the glycogen that was depeleted and also to repair and recover with the protein & Maltodextrin post workout shake, now if you are trying to cut carbs and you have to have some carbs during the day then that is when you take the low GI carbs, that will not raise your insulin levels, this will keep insulin levels low and allow you to burn fat during the day. Well that is my understanding.

 

[strong island]

Don't know if this helps...but here is some basic science. Glucose broken down into two simple sugars, sucrose, and fructose. These are the most basic forms of simple sugars used by the human body. Each form of the simple sugars is used by the body in the same way, and therefore it can be said that Fructose is no different for the body than Sucrose. Fructose is far more common than Sucrose in today's foods because of Corn Syrup. Consuming Fructose after a workout would be no different for the body than consuming a Coke (minus the carbonation). Whether or not it is beneficial to consume fructose after a workout...I have no idea, and people here will tell you a hundred different post-workout cocktails that may or may not have fructose. It's up to you.

Very bad misinformation....sucrose(table sugar) is a disaccharide. It is made from fructose and glucose, which are both monosaccharides.

Fructose is low GI because it does not affect blood sugar that much. This is because it is usually directly converted to glycogen in the liver.

Most people on this board (including myself) use dextrose(glucose) or glucose polymers (maltodextrin) after a workout because it raise blood sugar which in turn causes the pancreas to release insulin, which is needed to get all of that protein and other good stuff into our cells.

SI

 

[monkeyballs]

Very bad misinformation....sucrose(table sugar) is a disaccharide. It is made from fructose and glucose, which are both monosaccharides.

Fructose is low GI because it does not affect blood sugar that much. This is because it is usually directly converted to glycogen in the liver.

Most people on this board (including myself) use dextrose(glucose) or glucose polymers (maltodextrin) after a workout because it raise blood sugar which in turn causes the pancreas to release insulin, which is needed to get all of that protein and other good stuff into our cells.

SI

yep,
I take blame for that one.
Got my ose's mixed up...when sucrose is consumed it is broken down by the body to glucose and fructose. Not the other way around. Fructose is more common than sucrose however...more foods are sweetned with fructose than table sugar becasue it's cheaper.
There is evidence to suggest that high intake of fructose elevates the levels of serum triglycerides, thus increasing risks of diseases of the hearts and arteries. FYI- humans can live of intravenous glucose, but not intravenous fructose...severe derangement of liver function results.

 

[Riker29]

OK .......

But what I am looking for is this.

What about Fructose make sit different in terms of maybe heloing in a diet to lose fat, or to add fat....

And or during buling.

Like, lete get to real world examples.

The fact that it is LOW GI, ok ... does that mean that this would tend to promote MORE fat being made ... becuase its like a low, slow burn and therefore keeps blood sugar sliggtly evelvated for a log time, never allowiung it to drop....

Or maybe since its SO low on GI Index, that it never really tends to create an insulin spike ... so it actually is LESS able to promote creation of fat, or divesrion of glucose to fat.



I mean, look, in general I think most guys think the following (hope these are right):

Need SOME carbs to bulk

Need carbs for energy of workouts.

Needs carbs post workout to replenish muscles and help slam protein into them and rebuild tissue.

AFTER workouts is probably the best (and maybe ONLY) time to take HIGH GI carbs.

When not right after (or maybe before) a workout, best to NOT use High GI carbs becuae they make blood sugar go SO high, that invariably SOME of them go into making fat.



OK .. does that make sense?


BUT, what about Fructose would make it "different" in the above items?

 

[tury]

low GI doesnt raise insulin as much as high GI, high GI carbs should be taken immediately after your work out, and you can take them again for your very next meal after your workout meal or shake, this will inusre that you have fully replenished your muscles and or liver with all the glycogen that was depleted during your workout. as far as low GI carbs you can take those through out the day as your body craves them, this will satisfy your craving and these low GI carbs will constantly replenish your liver glycogen during the day and before your next work out. as well as quench your thirst for carbs.

 

[Riker29]

bump

 

[Vageta]

The answer you are looking for was answered in the 2nd post. Fructose has the unique property of refilling liver glycogen preferentially before going elsewhere. Fructose is also probably the least GI of any of the "sugars". This means it probably isn't a very good choice for post workout nutrition. After our workout we want a huge insulin spike to shuttle nutrients into the muscle and replenish muscle glycogen. Fructose will do neither of these things. That doesn't mean you can't sweeten up your post workout shake with some sort of fruit, but don't rely on this type of sugar as your only means of post workout carbs.

Now to answer some of your specific questions as to dieting. Fructose is the worst thing you can consume if you're tying to do a keto type diet. Why? Because ketosis revolves around liver glycogen. When the liver is completely depleted of glycogen it will eventually resort to ketones for fuel. However this can and does happen while there is still plenty of muscle glycogen available. If you were to ingest fructose at any point during a CKD then you would instantly kick yourself out of ketosis because you've just provided your liver with glycogen.

On this same note a TKD(targeted ketogenic diet) works because after a grueling workout you can refill muscle glycogen preferrentially over liver glycogen, presuming you don't ingest fructose as your post workout carb. Dextrose is the carb of choice here.

As far as the GI is concerned, I wouldn't concern myself over it much. It doesn't matter if the foods you eat have a GI of 10 or 100, if you eat more than you burn you will put on weight/fat end of story. There are those that would like you to believe that if you manage to keep insulin low you would never put on fat but this simply isn't true.

As far as fructose related to fat gain or loss, it is an excellent carb choice for just about any meal that isn't post workout. There are those who think fruit is a no-no while dieting but they are misinformed. Most fruits are great while dieting in moderation of course. Fructose has been proven in studies to be the carb LEAST LIKELY to lead to fat gain. Go over to T-mag and search for their article on fructose, it's a pretty good read.

Also there isn't such a thing as "too high" of a GI for postworkout nutrition. This is the one time you want to spike it as high as possible for as long as possible. Maltodextrin is the carb of choice as it has basically the highest GI you can get your hands on. This isn't something you're gonna want to eat at every meal while bulking though. You want slow burning carbs to provide your body with energy and nutrients and keep insulin levels steady to promote anabolism.

Also you need more than "some" carbs to bulk. You need a lot of carbs, more than protein and fat. A bulking diet 50% in carbs in not uncommon and as I said earlier it doesn't matter where you get your extra calories from. If you ingest more than you burn you will gain weight regardless if the extra calories are from protein or fat. Basic thermodynamics folks so you might as well get the benefits that carbs offer while bulking and not worry about which will cause more fat gain.

 

[strong island]

In my opinion ...fructose is very beneficial for most athletes. Since weight lifting does not fully utilize glycogen stored in our liver it is not that benefial for "bodybuilders." But if you are a distance runner or play soccer, tennis etc...fructose is very beneficial.

 

[cockdezl]

Fructose has been misrepresented in the bodybuilding press. T-Mag has about the best article that I have read concerning this topic. Essentially, it is excessive fructose consumption that is problematic, not the sugar itself.

Glucose is converted into glucose-6-phosphate in the body, which preferentially replenishes skeletal muscle glycogen, while fructose is converted into glucose-1-phosphate, which stores more as liver glycogen. The problem with fructose is that there is only so much fructose that the liver can convert at a given time. When this becomes too much, some gets shunted into triglyceride formation. This is the where the problems begin. Obviously triglycerides are fats and thus will store as fat, but they also interfere with insulin sensitivity. So too much fructose will cause fat storage and elevated insulin levels.

In the American diet, fructose has become the sugar of choice for sweetening foods, since it is sweeter than sucrose and very cheap to produce. Most soft drinks are primarily fructose and with the consumption of soft drinks we can see how this can become a problem very quickly.

 

[strong island]

Glucose is converted into glucose-6-phosphate in the body, which preferentially replenishes skeletal muscle glycogen, while fructose is converted into glucose-1-phosphate, which stores more as liver glycogen. The problem with fructose is that there is only so much fructose that the liver can convert at a given time. When this becomes too much, some gets shunted into triglyceride formation. This is the where the problems begin. Obviously triglycerides are fats and thus will store as fat, but they also interfere with insulin sensitivity. So too much fructose will cause fat storage and elevated insulin levels.

Good shit...I have to check that out.

 

[Riker29]

Wow! Jeezus guys, Thanks. Thanks a LOT.

This all has made this MUCH clearer to me, I really appreciate it.

I am not being sarcastic, I am being sincere, thanks again.

 

[MR. BMJ]

Fructose has been misrepresented in the bodybuilding press. T-Mag has about the best article that I have read concerning this topic. Essentially, it is excessive fructose consumption that is problematic, not the sugar itself.

Glucose is converted into glucose-6-phosphate in the body, which preferentially replenishes skeletal muscle glycogen, while fructose is converted into glucose-1-phosphate, which stores more as liver glycogen. The problem with fructose is that there is only so much fructose that the liver can convert at a given time. When this becomes too much, some gets shunted into triglyceride formation. This is the where the problems begin. Obviously triglycerides are fats and thus will store as fat, but they also interfere with insulin sensitivity. So too much fructose will cause fat storage and elevated insulin levels.

In the American diet, fructose has become the sugar of choice for sweetening foods, since it is sweeter than sucrose and very cheap to produce. Most soft drinks are primarily fructose and with the consumption of soft drinks we can see how this can become a problem very quickly.

I was wondering if you have the conversion of fructose-->Glucose-1-phosphate as a mistake?

Should it be Fructose------> Fructose-1-phosphate instead?

I have the fructose being phosphorylated by the Fructokinase enzyme into Fructose-1-phosphate.

BMJ

 

[D00fy]

STFU and eat the fucking fruit..........fuckin MODERATION is the key

oh no im gonna get fat from an apple let me run it off

#(_$(@#$(@_$(#$
fructose glucose stfu its all the same to me

thank you

 

[cockdezl]

Everyone should take notice from this post and never take anyone's posts as correct. As MR BMJ correctly pointed out, I am wrong in my original post. I was confusing fructose metabolism with galactose, where the latter goes to glucose-1-phosphate. Fructose is broken down in the liver to the two triose compounds, glyceraldehyde and dihydroxyacetone, which can continue on into glycolysis or go back into various pathways (glyceraldehyde can go to glycerol, which is needed for fat synthesis).

The main point is still that the enzymes that are responsible for fructose metabolism are in limited supply and when saturated will shuttle fructose or its byproducts into triglyceride synthesis.

 

[strong island]

Doofy...are you alright? You popping halos?

 

[Riker29]

I posted this on Anabolic Fitness and got an entirely different set of conclusions:

http://anabolicfitness.infopop.net/...12093973&m=6933076794&r=2453065205#2453065205

 

[Riker29]

bump