Posted: May 9, 2005

Sports Nutrition: Protein - The Building Blocks for Strength and Endurance

The Running Nutritionist’s ® Health, Food and Fitness Topics ©
Series I: Food as Fuel

Protein is a nutrient superstar to the exercising individual. Even though protein supplies only 5-10% of the energy required for sport (especially when the athlete is underfed, overtrained and/or competing in long distances), protein is critical for overall health. Without protein, life (and sport) would not exist.

Every working cell in the body has some form of protein. There are as many as 10,000 different proteins in every human cell. Some of the functions are structural as in hair, skin, bones and teeth. Others are functional like the building and repairing muscle tissues, regulating the body’s processes in digestion and metabolism, forming blood cells, making muscles contract, transporting other nutrients (like fat) around and protecting the body from infection. The body uses protein in the form of amino acids.

The Meaning of "Aminos"

While carbohydrates have repeating identical units in its structure, all amino acid chains are different. The sequence of amino acids is specified by heredity. This creates our own individual structure, mental and physical characteristics. That’s part of the reason why some excel at sports more than others do. Therefore, blame talent or lack of it on your ancestors!

Amino acids are either called essential or non-essential. Requirements for protein actually reflect amino acid needs. Of the 20 amino acids found in foods, nine cannot be made by the body and are called essential. Essential amino acids must come from the diet while non-essential is not diet dependent. Some essential amino acids are critical to sports performance because they’re needed in greater amounts by the exercising muscle.

Essential amino acids include: the Branched Chain Amino Acids (BCAA) Leucine, Isoleucine and Valine; Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Histidine* The non-essential are: Alanine, Arginine, asparagine, Aspartic Acid, Cysteine, Glutamic Acid, Glutamine, Glycine, Proline, Serine and Tyrosine

A dietary deficiency in one or more amino acids will cause a malfunction in one of protein’s structural or functional jobs. You’ll know this when you start to play poorly in your favorite sport, lose stamina, catch colds easily, have a poor complexion or a loss of hair, energy and muscle tone.

Animal products such as fish, chicken, meat, dairy and eggs contain all essential amino acids, while plants proteins may be limited in one or two. Most people don’t even realize that grains, vegetables, soy and nuts contain protein. These "incomplete" proteins need to be eaten in "complementary" combinations over the day to get all the essential aminos.

In addition to the food’s amino acid balance, the digestibility of protein is critical when comparing protein quality. Egg whites hold the highest score of 100%. Milk protein (casein) also has a 100. Soybeans are the best plant-based choice for the ideal amino acid profile.

How much is enough?

Research over the last 30 years have provided us with new techniques for estimating protein needs for endurance and strength athletes. These methods have shown that active individuals may benefit from up to 50-125% more protein above the current Recommended Daily Allowance (RDA).

The factors effecting dietary protein needs are:

* Total calorie intake
* Degree of training
* Intensity of training

The most important factor affecting protein requirement is calorie intake. Protein requirements decrease as energy intake increases. When food intake is restricted to reach a specific body weight, protein needs escalate. This is especially true for certain sports like wrestling, dancing and gymnastics.

Anaerobic exercise such as track repeats, cycling crits, and laser sailing races may also increase needs. Protein losses increase with a heavy training or at the onset of a new strenuous training program. There can also be losses up to ten days after a long distance event like the Ironman Triathlon. These losses can effect the immune system and muscle recovery. Anaerobic exercise such as track repeats, cycling crits, and laser sailing races may also increase needs. Protein losses increase with a heavy training or at the onset of a new strenuous training program. There can also be losses up to ten days after a long distance event like the Ironman Triathlon. These losses can effect the immune system and muscle recovery.

Protein Rx Protein Rx

There is no ideal protein recommendation, but simply a set of guidelines. This is due to fluctuations in training, conditions and life. To figure out your daily recommended protein intake:
1. Find your body weight
2. Convert your pounds into kilograms by taking pounds and dividing by 2.2 Convert your pounds into kilograms by taking pounds and dividing by 2.2
3. Multiply the following numbers to your kilogram number to figure out your daily protein needs.

Strength Athletes	Endurance Athletes	Early Season Training	Average Adult
Kilograms x 1.2-1.7	Kilograms x 1.2-1.4	kilograms x 2grams	kg x .8grams

4. During the trial period of at least two-four weeks, listen to your body carefully.

* Add additional protein when training heavier than normal or beginning a new program, feeling run down, lose hair, break out in pimples or get sick too easily
* Take away protein when you’re feeling heavy or dehydrated

Other Running Nutritionist’s ® Health, Food and Fitness Topics © related to this subject:

* Protein: The Anabolic Boost for Peak Athletic Performance
* Muscle Building Drinks, Bars and Potions: whole foods verses supplements
* Animal Free High Protein Diets: meeting needs without "meating" your needs
* Food and Mood: how specific amino acids can make your day

References and Recommended Reading:

Berning and Steen. Sports Nutrition for the 90’s. Aspen Publishers Inc., 1991.

Dorfman, Lisa. The Vegetarian Sports Nutrition Guide: Peak Performance for Beginners to Gold Medalists. John Wiley & Sons, 1999.

SCAN, Sports Nutrition, Second Edition: A Guide for the Professional Working with Active People, The American Dietetic Association, 1993.

Books from Lisa Dorfman:

Listen to Lisa's interview with EnduranceRadio.com.

Email your questions to Coach Lisa

Reprinted with permission from Lisa Dorfman at RunningNutrionist.com

Copyright © 2004 by Lisa Dorfman, MS, RD, LMHC. All rights reserved. Materials may be downloaded or printed for personal use only. Reproduction of any material contained on this web site is expressly prohibited, unless prior written consent is obtained from Lisa Dorfman