I see a lot of advice being given out about increasing protein consumption to build muscle mass, endurance and even to lose weight. Since the average person, (in America), already consumes approximately 30% of his caloric intake in protein, is there such a thing as eating too much protein and what might be the result of doing so?

To much protein you will gain fat, just like to many carbs 95-120 grms of protien a day is is enough for most endurance athletes. make sure you eat enough calories to maintain your weight or protien will get used for energy rather than for building, repairing, and maintaining body tissues, including muscle. if you eat poultry,fish,eggs,and milk products, getting enough protien shouldn't be a problem

Probably. There is concern about kidney damage from excess protein but this is not really clear. Most of this belief comes from people with renal disease who have been shown to have slower progression of their kidney damage with a lower protein diet. Does this extrapolate to those with normal kidney function? Not clear.

As zaskar said, if you have a diet with plenty of carbs and large amounts of protein, the excess protein will be used for stored energy. However, the recent trend towards low carb diets has made this less clear as people consuming plenty of calories (above what they are expending) but not many carbs can still lose weight.

I need to find out more about the particular study, but the claim is made that the average, active, healthy adult male uses less than 20 grams of protein per day. Americans consume an average of 160 grams per day.

I absolutely have to agree with this statement but more because people don't eat foods that are 100% protein and many of the more popular foods high in protein are also high in fat.

What exactly is the metabolic process for converting protein into fat? I've read that protein isn't stored, converted to carbohydrates or to fat and is only broken down and used to fuel muscles under extreme circumstances such as starvation. The rest of the time, excess protein is expelled through urine which is where the kidney damage patch70 mentions seems to come into the equation.

Could it be perhaps that at least some of the renal disease is caused or aggravated by all the excess protein the kidneys are forced to extract and expel over many years? I guess that's just a re-phrasing of your question but it's certainly an interesting one.

It's my understanding that the body doesn't really have a way to store protein. Perhaps this is where the idea comes from that one must always assure to consume enough protein?

According to Dr. John McDougal who is considered by many to be at the forefront of nutrition study; "There is no place for storage of any of the excess 140 grams of protein the average american consumes each day. The truth is you have to get rid of it. All of that excess protein is processed and eliminated by the liver and kidneys."

Comments made at:
http://entertainment.howstuffworks.c...hysiology2.htm

would also seem to indicate that protein is not normally used by the body for energy;

"Aerobic respiration can also use fatty acids from fat reserves in muscle and the body to produce ATP. In extreme cases (like starvation), proteins can also be broken down into amino acids and used to make ATP."

ATP, (adenosine triphosphate), is of course the molecule that the body uses to store and extract energy to fuel the muscles.

Given all the different information and comments it's easy to see from where all the confusion seems to arise. I suppose the information attained from studies utilizing rats in the 1940s didn't really help to give clarity to the situation since rats have completely different protein needs than humans.

Amino acids can be converted into ATP-derived energy. Thus, in excess, they can be stored. You are right that they are not stored as protein. They will via various metabolic pathways be stored as glucose/glycogen in the short term and as fat in the longer term.

Regarding renal damage from protein, most cases of renal failure can be explained by damage caused by diabetes, hypertension, reflux up the ureters, the glomerulonephritides or vasculitides, narrowing of the renal arteries, blockage of the ureters, or nephrotoxic drugs. There is not really good evidence to blame protein as the initial cause but it does appear to hasten progression of kidney failure.
That being said, if I was on a high protein diet, I would certainly make sure that I drank plenty of water.

[QUOTE]Originally posted by Beastt
[B]I need to find out more about the particular study, but the claim is made that the average, active, healthy adult male uses less than 20 grams of protein per day. Americans consume an average of 160 grams per day.


Remember i said 95 -120 grms daily for (Endurance Athletes) for non active every day people it is lower, 95-120 is based on a 150lb endurance athlete.

[QUOTE]What exactly is the metabolic process for converting protein into fat?


Sorry i have no anserw for this but very good question.

You're absolutely right. You did specify "endurance athletes" and I intended to be more clear about the fact that the 20 gram per day figure was for an "active" adult male which is pretty vague. The information I have even mentions an exception for "children, body builders and people recovering from injury". In checking back to my prior post, I see that I wasn't clear, as I'd hoped to be about the role played by levels of physical exertion.

I did find an interesting indicator of what an infant might need in terms of protein intake. When you consider the rapid growth and development of an infant, it's tempting to conclude that their protein requirements would be on the high end of the human scale. Human breast milk contains 5% protein by calories. Compare that to cow's milk at 15%, dog milk at 30% or rat milk at 49% and it would seem to indicate that humans require far, far less than the 30% that most Americans ingest. It might also suggest that cow's milk is perhaps a bit too rich in protein for the needs of active adult humans.

As far as the body builder is concerned, the only thing I've found to offer is a quote from Arnold Schwarzenegger. In referring to people who wish to follow Arnold in his pursuit of muscle mass, "...my formula for basic good eating: eat about one gram of protein for every two pounds of body weight."

I'm confused about converting animo acids into glucose and/or glycogen. From what I've found so far it appears that this is possible but only happens when the body has no carbohydrates to work with and occurs through a process called, "gluconeogenesis".

http://www.degussa-health-nutrition..../eng/kh/c5.htm

"Glucose is the most important fuel for the brain and red blood cells and is normally obtained from the diet. When fasting, however, the body’s glucose needs must be met by gluconeogenesis, the biosynthesis of glucose from non-carbohydrate precursors. Gluconeogenesis occurs in the liver and, to a smaller extent, in the kidneys."

Other comments seem to suggest that protein is either utilized for building/repairing tissues or discarded promptly.

Dr. David Reuben, "Raising the amount of protein you eat by 30% raises their, [providers of protein rich food products], income by 30%. It also increases the amount of protein in the sewers and septic tanks of your neighborhood 30% as you merrily urinate away everything that you can't use that very day.

There is nothing to clarify "use". I suppose that could include converting some to amino acids > glucose > glycogen > ATP but it seems to suggest to me that if the protein isn't directly put to use to repair/build tissues, it is expelled by the body rather than being stored in any form. I wish more clarification were provided.

I think if I were on a diet considered to be a high protein diet in comparison to the standard American diet, I'd be very tempted to substantially reduce protein intake. According to the research done by John Robbins and published in his first book, "I've found that not all authorities agree on the precise figure for our daily needs of protein, but their calculations do fall within a specific range. It is a range that runs from a low estimage of two and a half percent of our total daily calories up to a high estimate of up to eight percent."

It would be rather difficult to consume sufficient calories and not get at least 8% protein so to err on the side of safety would seem to suggest going low-protein rather than high.

As for some of the other causes of kidney disease you've provided, it's way over my head but it gives me that much more to try to learn about and add to an overall, informed conclusion. I appreciate all the input you and zaskar have provided. It seems to me that the continual over-consumption of protein is a subject worthy of further investigation.

Forgive me if I can't be bothered to go back to my old biochemistry textbooks but a decent one of these will go through the metabolic pathways for converting amino acids to energy.

Certainly but I believe the major problem for people in developed countries is over-consumption in general rather than just protein.

Not a problem at all about the text books. I'm sure I can find more information on it. It was your prior post on it that caused me to dig hard enough to find that it is possible.

I'm in complete agreement. As has been stated by some who know far more than I'll ever be able to pretend to know, "the diseases in this country, [U.S.], are not diseases of deficiency, they're diseases of excess."

Part of the reason for my specific interest in protien is that so many treat it like the miracle nutrient. Many act as though it would be nearly impossible to get too much of it. While people debate about low-carb, low-fat and suggest moderation in almost all things, (pretty good advice, it would seem), protein remains the one thing that "common knowledge" seems to tout as having no down-side.

I know this sounds a bit like stevek's belief about the commercial interests in promoting low-fat, but there exists sufficient evidence to believe that much of the "protein-worship" comes from some rather brilliant marketing strategies. It pays a lot more to promote what you're selling, (you need protein), than to promote not purchasing something, (low-fat).

I see protein routinely recommended as an energy source, even to the point of seeing protein bars and protein drinks being used pre-ride/exercise much as one might use a carbohydrate product.

Clearly our bodies need carbohydrates, fats and proteins but none of the three is the magical nutrient that protein is imagined to be in the minds of many.

That's a bit trite.

Carbs can't be converted into nitrogen bearing molecules!

Protein can be converted to glucose and used for energy. It's based on alanine.

So protein is an energy source and a repair source and what you have so eloquently chosen to omit is that protein INTAKE and/or the correct AA intake greatly ameliorates or entirely eliminates protein breakdown and BCAA usage for energy.

When you have TOO MUCH protein you are thirsty all the time and urine becomes more yellow due to excess ammonia needing to be eliminated.

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No doubt you're well versed in nutrition, Chemicalanarchy. But in this case I think I'm going to have to go with the experts in the field and they seem to strongly side against most of what you claim. As an example;

Dr McDougal:

"Digestion of protein begins in the stomach where acids and enzymes break it down into smaller components called amino acids. Some of the protein is immediately used to build skin, hormones and other tissues. Most of us use very little protein each day. The exceptions are children, body-builders and people recovering from injury. Studies have shown that an active, healthy, adult man uses less than 20 grams of protein a day. Americans consume an average of 160 grams of protein daily, or about 8 times what we need. Little if any is ever used as energy. Nor is protein converted into carbohydrates. Likewise protein is not converted to fat. There is no place for storage of any of the excess 140 grams of protein the average american consumes each day. The truth is you have to get rid of it. All of that excess protein is processed and eliminated by the liver and kidneys. In the process, this left over protein over-works these organs. As a consequence, they become enlarged and the kidneys slowly deteriorate over a lifteime. The loss of kidney tissue is insignificant for most people because of their reserve capacity. Normal function is maintained with as little as one quarter of the kidneys. However, someone who has lost kidney tissue from an accident, diabetes, atherosclerosis, an infection or another cause, can suffer life threatening damage to the kidneys from a diet that contains as much excess protein as the typical American diet.

Excess protein also causes changes in kidney metabolism. Minerals are also lost from the kidneys in large amounts, when they are called on to eliminate the excess protein., Particularly, animal proteins. Among the most important mineral lost is calcium from the bones which can lead to osteoporosis and kidney stones. Most of that damaging protein comes from animal sources, such as red meat, poultry, dairy products, eggs and fish.

Only in the most desperate situations, such as sever illness, or prolonged starvation will the body use the proteins in the tissues as fuel. People desperate to lose weight will often starve to lose. The body happily burns fat. But unfortunately, proteins from muscles and other important tissues are also consumed to survive. This is like burning your own house or at the very least, like burning your own oak furniture in your fireplace, rather than ordinary wood, to survive the cold."

Pritikin, Bernard and Robbins as well as several of the more trusted sources on the web all seem to be right in line with what Dr. McDougal states.

You need to do some exercise physiology research via medline, but thanks for the kidney scare.

And there is a HUGE difference between using quickly absorbed whey proteins over meat or whatever, but you know what, you keep doing it your way and I'll enjoy the view from up here!

And there is no proof of this whatsoever, ever in the history of humanity of this happening with healthy subjects.

'As a consequence, they become enlarged and the kidneys slowly deteriorate over a lifteime.'

All that indicates is how 'old school' you are.

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Amuse yourself:

What To Eat Before Cardio
One dilemma facing athletes is whether to eat anything before cardio, and if so, what. A recent study sheds some light on this and suggests the best option. (1).

The rationale for cardio on an empty stomach is obviously to increase fat burning. When carbs are taken in before exercise the carbs are preferentially used for fuel, sparing fat. On the other hand exercising on an empty stomach elevates cortisol levels which break down not only fats but muscle for fuel.

The other option is ingesting protein before exercise. This may spare muscle, but does it inhibit fat burning? Surprisingly, according to the study, it depends on the type of protein.

Rats were exercised under 4 different conditions. (1) Fasting. (2) Glucose meal before exercise. (3) whole milk protein before exercise (4) lactalbumin enriched whey before exercise.

At the end of the study, the glucose and milk protein fed rats gained fat mass, showing that these diets blunted the fat burning from exercise. The fasted rats lost both muscle and fat, whereas the whey fed rats lost just as much fat as the fasted rats, but gained muscle.

The moral is to burn fat and actually build muscle while doing cardio, ingest whey protein beforehand.

Am J Physiol Endocrinol Metab 2002 Sep;283(3):E565-72

A preexercise alpha-lactalbumin-enriched whey protein meal preserves lipid oxidation and decreases adiposity in rats.

Bouthegourd JC, Roseau SM, Makarios-Lahham L, Leruyet PM, Tome DG, Even PC.

Unite Mixte de recherche de Physiologie de la Nutrition et du comportement alimentaire, Institut National de la Recherche Agronomique, Institut National Agronomique Paris-Grignon, F75231 Paris, France.

The composition of the preexercise food intake is known to affect substrate utilization during exercise and thus can affect long-term changes in body weight and composition. These parameters were measured in male rats exercised 2 h daily over 5 wk, either in the fasting state or 1 h after they ingested a meal enriched with glucose (Glc), whole milk protein (WMP), or alpha-lactalbumin-enriched whey protein (CPalphaL). Compared with fasting, the Glc meal increased glucose oxidation and decreased lipid oxidation during and after exercise. In contrast, the WMP and CPalphaL meals preserved lipid oxidation and increased protein oxidation, the CPalphaL meal increasing protein oxidation more than the WMP meal. At the end of the study, body weight was larger in the WMP-, Glc-, and CPalphaL-fed rats than in the fasted ones. This resulted from an increased fat mass in the WMP and Glc rats and to an increased lean body mass, particularly muscles, in the CPalphaL rats. We conclude that the potential of the CPalphaL meal to preserve lipid oxidation and to rapidly deliver amino acids for use during exercise improved the efficiency of exercise training to decrease adiposity.

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AAAAAAAAAAAAAAHHHHHHHHHHHHHH!

' We conclude that the potential of the CPalphaL meal to preserve lipid oxidation and to rapidly deliver amino acids for use during exercise improved the efficiency of exercise training to decrease adiposity.'

Owwwwwwwwww!

During exercise, cortisol accelerates lipolysis, ketogenesis, and proteolysis (protein breakdown). This happens in order to provide additional fuel substrates for continued exercise. The effects of cortisol may also be necessary to provide an amino acid pool from which the muscle can rebuild new contractile proteins if there are insufficient amino acids delivered from the blood. This ensures that some degree of adaptation can occur regardless of the availability of dietary protein. Over time however, if this process is not balanced with additional dietary protein, the net effect will be only maintenance or even a decrease in functional muscle tissue, as is evident during periods of starvation or prolonged dieting. Fortunately, there is only a non-significant rise in cortisol levels when carbohydrates were consumed during exercise. (Tarpenning, 1998) The net effect is a more rapid increase in the cross sectional area of the muscle fibers with the greatest effect seen in type-II fibers.



Protein
Another pre-workout strategy involves taking advantage of increased blood flow to working muscles. Because the availability of amino acids is often the limiting factor for protein synthesis, a pre-workout protein meal will enhance the delivery of amino acids to muscle tissue. Research has demonstrated the effectiveness of a pre-workout protein drink.

Delivery of amino acids has been shown to be significantly greater during the exercise bout when consumed pre-workout than after exercise (Tipton, 2001). There is also a significant difference in amino acid delivery in the 1st hour after exercise, with the pre-exercise protein drink providing a significant advantage. Net amino acid uptake across the muscle is twice as high with a pre-workout protein drink as compared to consuming it after. Phenylalanine disappearance rate, an indicator of muscle protein synthesis from blood amino acids, was significantly higher when amino acids were taken pre-workout. These results indicate that the response of net muscle protein synthesis to consumption of a protein solution immediately before resistance exercise is greater than that when the solution is consumed after exercise, primarily because of an increase in muscle protein synthesis as a result of increased delivery of amino acids to the leg.

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