# Interesting article on Protein..



## Tuna_boi (Oct 30, 2004)

Well according to this im not getting enough protein, which I kind of knew anyways..I've just actually worked mine out properly and Im only getting around 150g a day at 98 kgs.So I need to up it to about 220g.

I know you guys all know about the correct intake anyways, but thought this makes an interesting read nonetheless.

The Right Amount of Protein for Athletes

by Ed Burke, Ph.D.

Without proper dietary support, metabolically stressful workouts and training regimens can result in more muscle damage than development, as well as disappointing strength and endurance gains

It's common knowledge that athletes need more carbohydrates than the average person. Less known is that athletes also need more proteins for the muscle growth and tissue repair that accompanies the tough physical demands they place on their bodies. Moreover, athletes need more amino acids-the building blocks of protein-for the numerous metabolic pathways and processes involved in exercise. Some amino acids, for example, influence hormone production and neurotransmission, physiological processes thought to influence athletic fatigue and performance.1

Basically, athletes need more protein than the average person because their workouts are more metabolically stressful. During periods of great physical exertion, the body steps up its use of the Amino Acids and proteins essential for oxidative energy production. If large amounts of protein are broken down and not replaced, athletes will go into a negative amino acid balance. They'll also be unable to compensate for the nitrogen their bodies lose during hard workouts. (Nitrogen is a byproduct of protein breakdown.) This, in turn, may have a negative effect on amino acid synthesis. Bodybuilders and other weight-conscious athletes such as wrestlers, dancers, gymnasts and female long-distance runners are most likely to be affected. Under certain circumstances, vegetarian athletes may also be at risk.

Athletes' Protein requirements increase during training. According to current knowledge, training amounts are approximately 1.2 to 2.0 grams of protein per kilogram of body weight per day for adults,2 compared to the Recommended Dietary Allowance (RDA) of 0.8 gram/kg. for non training adults. Assuming sufficient total caloric intake, this desired amount is likely to be present in any mixed diet that contains 12 percent to 15 percent of its energy as protein.

Interestingly, this value is consistent with most current macronutrient recommendations for athletes-a diet that is 60 percent to 70 percent carbohydrates, 12 percent to 15 percent protein and less than 30 percent fat. Although it is frequently said that high-protein diets may cause liver or kidney disorders, the possibility is not well documented and isn't a concern at these modest protein intake levels.3

Although the protein intake of many athletes-especially strength athletes and bodybuilders-substantially exceeds the RDA, many scientists erroneously consider these large quantities of dietary protein to be of little value.4 The protein RDA is only a broad-population guideline, however, and is based on data from relatively sedentary individuals.5 Recent studies using athletic subjects suggest that protein intake greater than RDAs is appropriate for some kinds of athletes.

Two decades ago, researchers demonstrated that a protein intake of 1.0 gram/kg. of body weight per day was sufficient to meet the needs of sedentary subjects. However, despite adequate total energy intake, this amount of protein was insufficient when these same subjects began an endurance (cycling) training program.6 Some reports on moderate exercise training suggest that the increased protein needs last only a few weeks at the beginning of an exercise program;7 but two recent studies involving more intense endurance exercise demonstrated increased protein requirements in individuals who had been training for several years.8,9

Perhaps both novice and experienced endurance athletes benefit from dietary protein in excess of the current RDA, but for different reasons. Novice athletes need protein to minimize loss of blood proteins, whereas conditioned athletes need it to provide amino acids for exercise fuel or muscle repair.10 If food energy intake isn't enough to support increased energy expenditure during training, or if food intake is restricted for weight loss, protein needs may increase.11 Under any of these circumstances, athletes consuming only 100 percent of the RDA for protein may experience decreases in muscle mass and strength.

Endurance Exercise And Protein Needs

Endurance exercise requires greater amounts of several amino acids as exercise fuel (especially the branched-chain amino acids such as leucine, isoleucine and valine).12 High exercise intensity, long periods of exertion, decreased carbohydrate availability and even stresses related to the exercise environment appear to promote greater amino acid oxidation.13 Such factors could alter rates of protein synthesis or breakdown and lead to an elevated dietary protein requirement of 1.2 to 1.4 grams/kg. of body weight per day.

Muscle damage occurs during endurance exercise, especially if it includes an eccentric component such as muscle tension that results from running downhill.14 Additional dietary protein might help repair these damaged muscle cells.

Strength Exercise And Protein Needs

It is well known that carbohydrates are very important for athletes who train extensively with weights. These athletes need to eat enough dietary carbohydrates to provide energy for their high-intensity exercises. In contrast, since strength training consists of short bouts of extremely intense effort, it would seem unlikely that amino acid oxidation is an important source of energy for such exercise. However, some published results suggest that additional dietary protein can also enhance strength gains.

Five of 10 elite weight lifters studied by Polish scientists were found by nitrogen balance methods to be consuming inadequate protein even when their protein intake was 2.0 grams/kg. of body weight per day.15 Unfortunately, one of these five athletes consumed a diet containing inadequate total calories. Because insufficient food intake elevates protein needs, the data from this individual are difficult to interpret. However, even when this subject is excluded, four of the 10 weight lifters had protein needs exceeding 2.0 grams/kg. of body weight per day.

In another study, five subjects whose diets consisted of 0.8 gram/kg. of body weight per day of protein and whose total calorie intake was adequate experienced a decreased cell mass (measured by potassium-40) over six weeks of strength training.16 With continued training and an increase in protein intake to 1.6 grams/kg. of body weight per day, their cell mass increased.

A study of nitrogen balance in bodybuilders demonstrated increased protein needs relative to controls and estimated the RDA for bodybuilders to be about 0.9 gram/kg. of body weight per day.17

Finally, impressive strength gains of 5 percent and size gains of 6 percent in world-class weight lifters were observed over several months of strength training when the athletes increased their dietary Protein from 1.8 grams/kg. to 3.5 grams/kg. of body weight per day.18

Compared to the protein intakes of most strength athletes, the protein levels that produced gains in muscle strength and size in the world-class weight lifters19 are greater than those suggested by most studies that use the nitrogen-balance technique.20 This may mean that although a positive nitrogen balance can be maintained during a strength-training program with a protein intake equal to or slightly above the RDA, higher intakes are necessary for optimal gains in muscle size and strength. Preliminary evidence for this exists in a study that found greater nitrogen retention (estimated from dietary nitrogen minus urinary nitrogen) and greater gains in lean body (muscle) mass during four weeks of strength training when subjects consumed 2.4 grams of protein per kg. body weight per day compared to 0.8 gram of protein per kilogram body weight per day.21

Together, the studies suggest that a protein intake in excess of the RDA will enhance the muscle strength and size gains induced by a strength program. Such a conclusion is somewhat speculative, however. Most of the studies use indirect or incomplete measurements and few subjects. Future studies with larger sample sizes and more direct measures are needed to confirm the observations.

People attempting to increase muscle strength and size through strength training might try consuming the equivalent of 1.2 to 2.0 grams protein to kilogram body weight per day (about 150-250 percent of the current protein RDA for adults).

Sources of Dietary Protein

In general, athletes' use of protein supplements during training is established and continually fostered. Luke Bucci, Ph.D., in his book, Nutrients As Ergogenic Aids For Sports and Exercise, says that protein powders are a more cost-effective source of protein per dollar than vegetables, grains, nuts, cheeses, fish and most beef products. Protein powders are less cost-effective, however, than powdered milk, eggs, chicken or pork.22

Except for nonfat powdered milk, foods that are less costly than protein powders generally contain considerable quantities of fat and excess calories that athletes such as bodybuilders are trying to avoid. For the cost of a nice dinner out or a one-week supply of meat, athletes can buy a month's worth of Protein Powder-approximately 50 grams per day of supplemental protein. That's why many athletes view protein powders as a cost-effective and convenient sources of additional dietary protein. For these reasons alone, protein supplements will remain in demand.

Two other forms of protein supplementation have recently hit the market23-protein hydrolysates and free-form amino acid mixtures. Hydrolysates are the single amino acids, dipeptides and tripeptides, that are made by putting intact proteins into either an enzyme or acid bath and breaking them apart. Enzymatic hydrolysis retains the serine, threonine, tryptophan, cysteine and salts that are often lost during acid hydrolysis.

An ever-increasing number of hydrolysates are commercially available. Despite the lack of evidence, some companies claim their products improve or hasten absorption better than dietary proteins or even amino acid mixtures do. However, such protein hydrolysate products are two to five times more expensive than protein powders containing the same amount of nitrogenous material.

Amino acid mixtures have lately gained in popularity now that large amounts of food-grade L-amino acids are readily available. Most free-form amino acids are produced in Japan by microbial fermentation. That's why relying on free-form amino acids as a sole dietary nitrogen source gets expensive.24

Proponents of free-form amino acid mixtures claim that absorption is complete and the mixtures are totally digested. They also claim that absorption of nitrogen is more rapid than from proteins and that amino acid compositions can be manipulated to optimize energy or protein synthesis for athletes. Various physiological parameters such as hormone release are also purported to be influenced. However, more research is needed to support the claims of manufacturers of free-form amino acid mixtures.

Other inconclusive data suggest that individual amino acid supplementation may benefit some types of exercise performance. Branched-chain amino acids, tryptophan, glutamate, aspartate and potential growth hormone-stimulating amino acids are among the amino acids being investigated.25 This is an area where additional research is needed because very few studies have documented actual performance-enhancing effects.

Summary

It is safe to say that serious athletes require protein levels that exceed the RDA. Although definitive dietary recommendations for various athlete groups must await future study, much current evidence suggests that strength athletes and bodybuilders should consume up to 2.0 grams/kg. of body weight per day (250 percent of RDA) and endurance athletes up to 1.4 grams/kg. of body weight per day (175 percent of RDA). These quantities can be obtained from a diet that consists of 12 percent to 15 percent energy from protein, unless total dietary energy intake is insufficient. It should be noted, however, that too much of an increase in dietary protein over the long run may have some detrimental effects. Such a program should be overseen by a physician.


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## Killerkeane (Nov 9, 2003)

good read tuna boi


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## jas uk (Sep 7, 2004)

very interesting I thought eating meat was cheaper than powders?


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## dub_town_153016 (Sep 23, 2005)

can some 1 hit me up and tell me all da protine stuff to eat please


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