PDA

View Full Version : Different carb sources and muscle/liver glycogen



anasthetic
11-23-2005, 02:50 PM
This question stems from my lack of clarity about how carbs refill different ratios of muscle/liver glycogen, and the practical implications of this on both pre/post workout nutrition as well as general body composition nutrition.

This is referring to fructose, sucrose, lactose, dextrose, corn syrup/HFCS, carbs from grains, carbs from potatoes, carbs from legumes, and any other carbs I've forgotten about.

Some possible questions arising from this topic: Are there times of day where fruit (fructose) is ideal? Is fruit really that bad PWO? Does corn syrup really turn to fat more readily than sucrose?

anasthetic
11-23-2005, 04:32 PM
Judging from the lack of response from forum junkies, I'm guessing a lot of this information simply isn't fully understood at the current time. If anybody can definitively say that nobody knows for sure the answer to any of the questions, I'd be interested to know that as well.

Slim Schaedle
11-23-2005, 08:44 PM
Judging from the lack of response from forum junkies, I'm guessing a lot of this information simply isn't fully understood at the current time. If anybody can definitively say that nobody knows for sure the answer to any of the questions, I'd be interested to know that as well.
In reference to your question about fructose, here is something I posted a few days ago in another thread concerning the body's absorption and use of fructose. It might shed some light on what you are asking.

Personally, strictly in terms of carbohydrate utilization, I see no need for fructose (fruits) Vitmains/phytochemicals beneficial to the body is a different story. ( but I still don't eat fruit)

Techinally, your muscles don't process fructose, glucose, or any sugar or complex carb. It is the liver that does it.

Fructose can be "processed" in two ways.

First, being converted to Fructose 6-phospate, and then to glucose 6-phophate, then eventually being converted to glyocogen through glycogenesis OR , through glycolysis, be converted to fructose 1,6 biphosphate and eventually be converted to pyruvate or lactate

Second, fructose can be directly converted to fructose 6-phosphate and eventually be converted to pyruvate and enter the Krebs cycle. (or converted to lactate in anaerobic conditions)

Note: The second method is slow and only occurs in presence of large amounts of fructose, which can actually deplete ATP and reduce the rate of other biosynthetic processes such as protein synthesis (and that's bad)

To sum it up, there is no circulation of fructose in the bloodstream.



I have some pretty detailed info on carb absorption, "processing" etc. up my sleeve, so just ask some specific questions and I'll give you whatever I have. If the scientific jargon is consfusing, just let me know.

Holto
11-24-2005, 09:33 AM
Are there times of day where fruit (fructose) is ideal?

Morning. Your hepatic glcogen is low.


Is fruit really that bad PWO?

If fructose is the only sugar you have PWO then I say yes.



Does corn syrup really turn to fat more readily than sucrose?

Fat in the blood does not necessarily mean fat added to the body. Fat is also a source of energy. Eating HFCS does not effect fat gain.