Exercise and substrate oxidation studies

[xAlphax]

How much protein is used for energy during continuous exercise? I was thinking somewhere in the range of 5-15% out of total calories burned but have had no luck finding concrete studies comparing/contrasting this with glycogen and fat. Also does the intensity of exercise affect this number greatly, fasting conditions, current state of nitrogen balance?

[rgurleyjr]

How much protein is used for energy during continuous exercise? I was thinking somewhere in the range of 5-15% out of total calories burned but have had no luck finding concrete studies comparing/contrasting this with glycogen and fat. Also does the intensity of exercise affect this number greatly, fasting conditions, current state of nitrogen balance?

I believe I've read that protein oxidation can provide 5-10%. Check out this page. http://www.xtremeo2.com/page/page/3950537.htm

[xAlphax]

I believe I've read that protein oxidation can provide 5-10%. Check out this page. http://www.xtremeo2.com/page/page/3950537.htm

That's great, but the studies mentioned seem a little too void of info to actually search for them here.

[iCY]

How much protein is used for energy during continuous exercise? I was thinking somewhere in the range of 5-15% out of total calories burned but have had no luck finding concrete studies comparing/contrasting this with glycogen and fat. Also does the intensity of exercise affect this number greatly, fasting conditions, current state of nitrogen balance?

How would you use this info? During fasting conditions, cellular protein would be degraded to provide intermediates for gluconeogenesis..

[thegymbum]

It can vary manifold depending on your fed state. If you're in starvation state, and have depleted reserves of fat and glycogen, it can be quite a bit higher, probably up to half. When there's glycogen and fat available, it significantly drops.

[rgurleyjr]

http://www.alfediam.org/media/pdf/Re...nD&M2-2001.pdf

Everything you wanted to know about, this is long but great and full of studies. I haven't read it lately, but yes, the lower your glycogen stores are, the more protein will get oxidized but it's not the first resort like so many misinformed meatheads on here believe. I remember reading in that link that as glycogen gets low, the body will begin to oxidize more fat to conserve it. The body is very smart, smarter than we are!

[xAlphax]

How would you use this info? During fasting conditions, cellular protein would be degraded to provide intermediates for gluconeogenesis..

Dunno lol

It can vary manifold depending on your fed state. If you're in starvation state, and have depleted reserves of fat and glycogen, it can be quite a bit higher, probably up to half. When there's glycogen and fat available, it significantly drops.

That's another thought, how long before you deplete fat stores? It seems to me that the body would struggle trying to keep the fat burning going after a bunch of exercise before depleting would ever be aproblem.

http://www.alfediam.org/media/pdf/Re...nD&M2-2001.pdf

Everything you wanted to know about, this is long but great and full of studies. I haven't read it lately, but yes, the lower your glycogen stores are, the more protein will get oxidized but it's not the first resort like so many misinformed meatheads on here believe. I remember reading in that link that as glycogen gets low, the body will begin to oxidize more fat to conserve it. The body is very smart, smarter than we are!

Thanks ill be sure to check it out.