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Nutrition, nutrition, nutrition

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Nutrition, nutrition, nutrition

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Old 07-11-18, 04:58 AM
  #26  
livedarklions
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Originally Posted by Dudelsack View Post

Support your bold claim. I know you metabolise fat because itís the ultimate high-density energy source. Are you maintaining that muscle breakdown occurs so it can feed into gluconeogenesis? Is this a more efficient means, from the bodyís energy economy?
Bold claim??!! You really aren't aware of muscle catabolism as a source of energy during prolonged aerobic exercise? That's so basic, you can just Google it. Your comment is a great example of a little knowledge being a dangerous thing. Your body, when needing large amounts of quick calories is going to follow multiple paths, including breaking down amino acids. BTW, the reason ketogenic diets limit proteins is because the body breaks down amino acids into glycogen to take you out of ketosis. That ought to tell you something about assuming the body is preferring the "more efficient" means exclusively . Add to this that if you restrict protein to maintain ketosis, your body won't have adequate amounts of amino acids available to repair the muscles damaged by prolonged aerobic exercise.

I'll leave it to medical people to let you know whether it's actually dangerous. I would suspect it is. Ketosis and elevated cortisol sounds like a bad combo to me.
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Old 07-11-18, 05:28 AM
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Originally Posted by Dudelsack View Post

Is there any evidence that Clif bars are a better source of energy than, say, a BP&J? Lara bars are the fave if your gluten-free and sugar free (kind of) but does that make it a better source of energy on rides?
Nope, but like's been said, they're quick and easy. I use PB2 (the powdered peanut butter, and honey or sometimes nutella.) I enjoy the sammiches more, but the bars are more convenient at times.
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Old 07-11-18, 08:04 AM
  #28  
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Originally Posted by livedarklions View Post
Bold claim??!! You really aren't aware of muscle catabolism as a source of energy during prolonged aerobic exercise? That's so basic, you can just Google it. Your comment is a great example of a little knowledge being a dangerous thing. Your body, when needing large amounts of quick calories is going to follow multiple paths, including breaking down amino acids. BTW, the reason ketogenic diets limit proteins is because the body breaks down amino acids into glycogen to take you out of ketosis. That ought to tell you something about assuming the body is preferring the "more efficient" means exclusively . Add to this that if you restrict protein to maintain ketosis, your body won't have adequate amounts of amino acids available to repair the muscles damaged by prolonged aerobic exercise.

I'll leave it to medical people to let you know whether it's actually dangerous. I would suspect it is. Ketosis and elevated cortisol sounds like a bad combo to me.
​​​​
Google it? Sounds like a good idea. This is what I found:

Btw , I’m quoting this verbatim, it’s not an original reply.

The myth about burning muscle.

Because this topic has come up many times, I decided to do some research on it and get the scientific answer.

The order in which your body uses fuel is: glucose --> glycogen --> fat --> protein. Your body uses glucose and glycogen as the main energy sources. You use fat as the next energy source. The body rarely, if ever, breaks down protein and uses it for energy.

As far as “burning muscle”, I found the below. This is highly simplified, but I found many references that support it. This is what happens if you’re fasting; if you are NOT eating at all.

Basically, for energy the body uses glucose as its primary fuel. It gets glucose from breaking down carbohydrates. Any glucose not used immediately is stored in the liver as glycogen. Your glycogen reserves last about 6 hours.

After you run out of glycogen, your body starts breaking down fats for energy. It will do this for about 2-3 days.

Starting around the 4th day of fasting, your body begins to synthesize ketone bodies from fatty acid breakdown. This primarily fuels the brain and not the body (about 70%).

DEPENDING ON HOW MUCH STORED FAT YOU HAVE (your body fat percentage), once you’ve been fasting for approximately 5 days to 3 weeks, and the ketone bodies are depleted, your body starts to break down protein, which is converted into glucose by the liver. This protein will come from your muscles and your body organs.

Keep in mind, the above is if you’re NOT eating at all. If you have a good nutrition plan, even if it’s a calorie-deficit one, you’re not going to “burn” muscle.

EDITED TO ADD IN THIS MORE SCIENTIFIC EXPLANATION BY MEDX:

Quote from: MedX on February 24, 2010, 08:28:14 AM
Your body doesn't really store protein, it uses it to build body tissues. There is a huge amount of misinformation about "burning muscle/protein" as a fuel source. The truth according to current physiology and biochemistry research is that the body spares and recycles protein whenever possible.

As part of its normal regeneration process, your body is constantly breaking down damaged cells into amino acids which are then reutilized by the creation of new peptide bonds to make new proteins for construction of new tissue. This cell turnover is very necessary to maintain healthy tissues. The slowing of this process is one of the components that causes physiological decline associated with aging.

When carbohydrate reserves are exhausted, the liver can convert proteins into fatty acids, ketone bodies, or glucose. Before amino acids (the building blocks of protein) can be catabolized, they must be converted into substances that can enter the Krebs cycle for oxydation or converted to glucose/glycogen. The process of converting amino acids into carbohydrate (glucose) is called gluconeogenesis. It is actually rather difficult for the body to convert protein to carbohydrate in order to burn it. It only happens in significant quantities in two situations, during extreme high energy demand when glycogen and blood glucose are exhausted but before fat stores (lipids) can be converted into glyceraldehyde and then to glucose, or, in periods of starvation when both carbohydrate and lipid stores are exhausted.* The first proteins to be utilized are the free proteins and amino acids in the blood. The body will not cannibalize (notice the distiction from catabolization) healthy muscle or vital organ tissue exept in extreme circumstances.

Another cause of muscle loss is atrophy due to disuse, such as is seen when muscles are immobilized in a cast for an extended period. Some illnesses can also cause muscle wasting. Overtraining without adequate recovery also interferes with muscle growth and repair.

So, as long as you have decent nutrition with normal glycogen and glucose stores, have some non-essential bodyfat (above 5% or so in adult males) and adequate dietary protein, you will not "burn" significant amounts of muscle tissue as the result of resistance training or aerobic exercise. You still need to allow adequate recovery time based on your own physiology to avoid overtraining.

*Source: Advanced Principles of Anatomy and Physiology by Tortora and Grabowski, Harper Collins Press
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Old 07-11-18, 10:56 AM
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From your source:

Originally Posted by Dudelsack View Post

"It only happens in significant quantities in two situations, during extreme high energy demand when glycogen and blood glucose are exhausted but before fat stores (lipids) can be converted into glyceraldehyde and then to glucose, or, in periods of starvation when both carbohydrate and lipid stores are exhausted.*"

Say, for example, on a long bike ride after you've exhausted the glycogen and your blood glucose is low because you don't take in carbs?

To the extent that we have an argument, it probably is over our definitions of "long" bike rides. Mine definitely includes extreme high energy demand over more than 6 hours. I'm quite sure I'd screw myself up if I didn't take in some carbs over 140 miles in a day.
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Old 07-11-18, 11:09 AM
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When I read explanations like this, I can follow along, but ask me tomorrow to explain it, and it would be tough.

Still I appreciate that you took the time to post precise, well-sourced information about what's going on. It amazed me how little I know about the basics of metabolism; it's a wonder that it all works so well despite my intellectual ignorance.
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Old 07-11-18, 11:37 AM
  #31  
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Originally Posted by Dudelsack View Post

Google it? Sounds like a good idea. This is what I found:

Btw , I’m quoting this verbatim, it’s not an original reply.

The myth about burning muscle.

Because this topic has come up many times, I decided to do some research on it and get the scientific answer.

The order in which your body uses fuel is: glucose --> glycogen --> fat --> protein. Your body uses glucose and glycogen as the main energy sources. You use fat as the next energy source. The body rarely, if ever, breaks down protein and uses it for energy.

As far as “burning muscle”, I found the below. This is highly simplified, but I found many references that support it. This is what happens if you’re fasting; if you are NOT eating at all.

Basically, for energy the body uses glucose as its primary fuel. It gets glucose from breaking down carbohydrates. Any glucose not used immediately is stored in the liver as glycogen. Your glycogen reserves last about 6 hours.

After you run out of glycogen, your body starts breaking down fats for energy. It will do this for about 2-3 days.

Starting around the 4th day of fasting, your body begins to synthesize ketone bodies from fatty acid breakdown. This primarily fuels the brain and not the body (about 70%).

DEPENDING ON HOW MUCH STORED FAT YOU HAVE (your body fat percentage), once you’ve been fasting for approximately 5 days to 3 weeks, and the ketone bodies are depleted, your body starts to break down protein, which is converted into glucose by the liver. This protein will come from your muscles and your body organs.

Keep in mind, the above is if you’re NOT eating at all. If you have a good nutrition plan, even if it’s a calorie-deficit one, you’re not going to “burn” muscle.
<snip>
I didn't want to take up space by quoting your entire post.

Try googling "endurance exercise protein metabolism". You'll see that our bodies break down protein at a fixed rate as a percentage of carbohydrate use. Intensity increases that rate. Endurance training decreases it, however it also increases our body's capacity for protein breakdown, probably because the trained athlete can maintain higher carbohydrate burn rates. Hammer has a good article on dietary protein for endurance here: https://www.hammernutrition.com/know...-much-protein/

I'm not going to bore the reader by quoting that article. If you're interested in endurance fueling, it's a good read. I've been following their fueling plan, though not with their products, for over 20 years. Works well.

My long distance ride fuel is 15% protein. I usually eat about half of my total burn, which is all my stomach can tolerate. Last year at this time, I did a 7 hour ride in the mountains with a total burn of about 4000 calories. I went through 1500 calories of my fuel, plus some snack foods. 15% of 1500 is 225 or 56g protein. That seems just right to me, trying for 120g for the day or 1.7 * 70kg. I could still hit lactate threshold and sprint at the end of the ride, so it all worked well.

I'll be doing that same training ride this coming Sunday, following that same fueling plan.

Those who want to see some scientific data on protein requirements, have a look at this PDF: http://journals.plos.org/plosone/art...type=printable
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Old 07-11-18, 01:44 PM
  #32  
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I'm 64 and I always eat whatever I want and usually too much of it. When on longish rides I prefer regular food (sandwiches, fruit) over bars or gels. Gels, in fact, upset my stomach.
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Old 07-11-18, 06:37 PM
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Originally Posted by Carbonfiberboy View Post
I didn't want to take up space by quoting your entire post.

Try googling "endurance exercise protein metabolism". You'll see that our bodies break down protein at a fixed rate as a percentage of carbohydrate use. Intensity increases that rate. Endurance training decreases it, however it also increases our body's capacity for protein breakdown, probably because the trained athlete can maintain higher carbohydrate burn rates. Hammer has a good article on dietary protein for endurance here: https://www.hammernutrition.com/know...-much-protein/

I'm not going to bore the reader by quoting that article. If you're interested in endurance fueling, it's a good read. I've been following their fueling plan, though not with their products, for over 20 years. Works well.

My long distance ride fuel is 15% protein. I usually eat about half of my total burn, which is all my stomach can tolerate. Last year at this time, I did a 7 hour ride in the mountains with a total burn of about 4000 calories. I went through 1500 calories of my fuel, plus some snack foods. 15% of 1500 is 225 or 56g protein. That seems just right to me, trying for 120g for the day or 1.7 * 70kg. I could still hit lactate threshold and sprint at the end of the ride, so it all worked well.

I'll be doing that same training ride this coming Sunday, following that same fueling plan.

Those who want to see some scientific data on protein requirements, have a look at this PDF: http://journals.plos.org/plosone/art...type=printable
Cool article. Thanks.
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Old 07-12-18, 02:09 PM
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Agree, good info!

I rely on shorter, harder rides because of the demands of work and other sports and because I have no friends. I take a protein supplement after every ride or gym session, but I still have the very devil of a time adding and maintaining upper body mass. Now, in my early 60s, because of adding the whey protein and upping the weight training, I'm holding onto muscle better than earlier my life.

I really want to go into old age with some strength and bulk. My primary care doc (actually an NP at a military facility at the time) once looked at me with my shirt off and said, "You know, you're one norovirus away from the hospital, pal." Another time she said, "Hey, the camps have been liberated." I kept telling her, "it's fast."
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Old 07-12-18, 10:39 PM
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Originally Posted by MoAlpha View Post
Agree, good info!

I rely on shorter, harder rides because of the demands of work and other sports and because I have no friends. I take a protein supplement after every ride or gym session, but I still have the very devil of a time adding and maintaining upper body mass. Now, in my early 60s, because of adding the whey protein and upping the weight training, I'm holding onto muscle better than earlier my life.

I really want to go into old age with some strength and bulk. My primary care doc (actually an NP at a military facility at the time) once looked at me with my shirt off and said, "You know, you're one norovirus away from the hospital, pal." Another time she said, "Hey, the camps have been liberated." I kept telling her, "it's fast."
Look at the climbers! Deathly skinny.
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