Protein Requirements for Athletes

A well-designed diet for an athlete is a combination of proper energy intake, proper timing, along with proper training. An energy deficient diet during training may lead to loss of muscle mass and strength, increased susceptibility to illness, and increased prevalence of overreaching and/or overtraining (7). People who follow a general fitness program can generally meet their nutritional needs with a healthy, well-balanced diet. However, the caloric and protein needs of a highly trained athlete are different
and will be discussed here.

Considerable debate ensues regarding the proper intake of protein for athletes. The current recommended level of protein intake (0.8 g/kg/day) is estimated to be sufficient to meet the needs of nearly all (97.5%) healthy men and women age 19 years and older (2). This amount of protein intake may be appropriate for non-exercising individuals, but it is “likely not suffi cient to off set the oxidation of protein/amino acids during exercise (approximately 1 –5% of the total energy cost of exercise)” (2). If an athlete does not ingest sufficient amounts of protein, he or she will maintain a negative nitrogen balance, which can increase protein catabolism and slow recovery (7). Nitrogen balance is quantifed by calculating the total amount of dietary protein that enters the body and the total amount of the nitrogen that is excreted (9). Table 1 provides general guidelines for protein and caloric intake based on the level of activity.

It is important to remember that not all protein is the same. Proteins differ based on the source, the amino acid profile and the methods of isolating the protein (7). Great dietary sources of low-fat, high-quality protein are skinless chicken, fish, egg whites and skim milk while the highest quality supplemental sources are whey, colostrum, casein, milk proteins and egg protein (7). The Food
and Agriculture Organization (FAO) established a method for determining the quality of a protein source by “utilizing the amino acid composition of a test protein relative to a reference amino acid pattern and then correcting for differences in protein digestibility,” (4).

Two of the most widely used protein supplements are casein and whey, which can both be found in milk products. Research has demonstrated that “whey protein elicits a sharp, rapid increase of plasma amino acids following ingestion, while the consumption of casein induces a moderate, prolonged increase in plasma amino acids that was sustained over a 7-hour postprandial time period,” (1). The International Society of Sports Nutrition (ISSN) recommends that athletes obtain protein through whole foods, and when supplements are ingested they should contain both casein and whey “due to their ability to increase muscle protein accretion,” (2).

While casein and whey have been found to be beneficial, other research exists to support the benefits of leucine. Approximately one third of skeletal muscle protein is made up of the branched-chain amino acids (BCAA), leucine, isoleucine and valine (8). Research suggests that of these three, leucine plays the most significant role in stimulating protein synthesis (5). Therefore, supplementation
of branched-chain amino acids may be beneficial to athletes.

Researchers at the Department of Human Biology at Maastricht University in the Netherlands, conducted a study to determine post-exercise muscle protein synthesis and whole body protein balance following the combined ingestion of carbohydrates with or without protein and/or free leucine (6). Eight male subjects were randomly assigned to three trials in which they consumed drinks containing carbohydrates, carbohydrates/protein, or carbohydrates/protein/leucine following 45mins of resistance exercise. Results of the study showed that whole body protein breakdown rates were lower, and whole body protein synthesis rates were higher in the carbohydrate/protein and carbohydrates/protein/leucine trials compared with the carbohydrate trial. The addition of leucine resulted in a lower protein oxidation rate compared with the carbohydrate/protein trial. The study concluded that
co-ingestion of protein and leucine stimulates muscle protein synthesis and optimizes whole body protein balance compared
with the intake of carbohydrates only (6).

BCAA supplementation has been shown to be particularly beneficial during aerobic exercise because of an increase in the free tryptophan/BCAA ratio (5). During prolonged aerobic exercise, the amount of free tryptophan increases and therefore the amount of tryptophan entering the brain increases, resulting in fatigue (5). BCAAs are transported to the brain through the same carrier as tryptophan, so when BCAAs are present in the plasma, in signifi cant amounts, they may decrease the amount of tryptophan reaching the brain, therefore decreasing feelings of fatigue (2). It has been suggested that the recommended daily allowance (RDA) for leucine alone should be 45 mg/kg/day for sedentary individuals, and even higher for active individuals (8). A deficiency in BCAA intake from whole foods can be supplemented by consuming whey protein (2).

In conclusion, major organizations recommend athletes consume more than the RDA for protein, approximately 1.4 – 2.0 g/kg of body weight/d (2,4). Every attempt to obtain protein from whole foods is ideal; however supplementation is a safe way of obtaining the needed amounts of protein when necessary.

Table 1. Caloric and Protein Intake Guidelines

Activity Level Caloric Intake Protein Intake
General Activity 25 -35 kcals/kg/day 0.8 – 1.0 g/kg/day
Strength Training Athletes 50 – 80 kcals/kg/day 1.4 – 1.8+ g/kg/day
Endurance Athletes 150 – 200 kcals/kg/day 1.2 – 1.4 g/kg/day

Source: The Position Statement from the Dietitians of Canada, the American Dietetic Association, and the American College of Sports Medicine, Canadian
Journal of Dietetic Practice and Research in the Winter of 2000, 61(4):176-192 (3).


1. Boirie Y, Dangin M, Gachon P, Vasson MP, Maubois JL, and Beaufrere, B. Slow and fast dietary proteins differently modulate postprandial protein accretion. Proceedings of the National Academy of Sciences of the United States of America 94(26): 14930 – 5, 1997.

2. Campbell, B, Kredier, R, Ziegenfuss, T. et al. International Society of Sports Nutrition position stand: Protein and exercise. Journal of the International Society of Sports Nutrition 4(8), 2007.
3. The Position Statement from the Dietitians of Canada, the American Dietetic Association, and the American College of Sports Medicine. Canadian Journal of Dietetic Practice and Research 61(4): 176 – 192, 2000.
4. Darragh, A, and Hodgkinson, S. Quantifying the digestibility of dietary protein. The Journal of Nutrition 130: 1850S – 1856S, 2000.

5. Kimball, SR, and Jefferson, LS. Signaling pathways and molecular mechanisms through which branched-chain amino acids mediate
translational control of protein synthesis. Journal of Nutrition 136(1 Suppl): 227S – 31S, 2006.

6. Koopman R, Wagenmakers AJ, et al. Combined ingestion of protein and free leucine with carbohydrate increases post-exercise muscle protein synthesis in vivo in male subjects. American Journal of Physiology Endocrinology and Metabolism 288(4): E645 – 53, 2005.

7. Kreider, RB, Wilborn, CD, Taylor, L, Cambpell, B, et al. ISSN exercise & sport nutrition review: Research & recommendations. Journal of the International Society of Sports Nutrition 7(7.2), 2010.

8. Leucine supplementation and intensive training. Sports Medicine. 27(6): 347 – 58, 1999.

9. Rand WM, Pellett, PL, and Young, VR. Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults. American Journal of Clinical Nutrition 77(1): 109 – 27, 2003.


Are Supplements a True Substitute for Real Food?
While some may have predicted that the day would come when we no longer needed to eat food and could derive the nutrients our bodies needed from taking a pill, that day is not yet here. And the more we learn about food and nutrients, their roles and interactions, the more scientists realize that this day may never come. Through decades of research, we have learned that foods provide far more than just calories, vitamins and minerals. Food provides other important nutrients like antioxidants, phytochemicals and fiber which reduce the risk of a number of chronic diseases including cancer, cardiovascular disease, diabetes
and age-related macular degeneration (1,6). Supplements have yet to offer these “ingredients” or even this
same protection (3).

In light of the possible limitations of supplements, does anyone really need to take one? While it is hard to make
a blanket statement such as “all children” or “all pregnant women” require a supplement, there are certain categories and instances where we can make certain generalizations.

Supplements are a multi-billion dollar industry with people under the false impression that taking supplements is improving their health and/or performance (4). Can we rely on supplements to provide us with additional vitamins and minerals not found in a well balanced diet? Perhaps. But supplements are not regulated as drugs; they are regulated as food, in accordance with the Dietary Supplement Health and Education Act (DSHEA) passed by Congress in 1994. The result is that the FDA has very little regulation over the supplements sold in this country— they do not analyze the content of dietary supplements nor do they approve the labels on the bottle. Additionally, the FDA can only remove a product from the market after it has been proven unsafe. Usually a supplement is proven unsafe and removed from the market after people taking it get sick or even die.

So what can athletes and individuals who are interested in taking a supplement do to protect themselves? Fortunately, there are two tools available to help consumers choose a safe supplement. One is to look for the U.S. Pharmacopeia or “USP” seal. The “USP” seal means that the product has been independently tested and reviewed by USP to verify ingredient and product integrity, purity, and potency for the manufacturers who choose to participate (7). However, it does not mean that this supplement has been tested for safety or effectiveness. Another option is to search the supplement reviews available on ConsumerLab.com, which is an independent, non-profit testing agency. This organization selects products and tests for accuracy of content (e.g., a supplement that says it contains 400 IU of vitamin D actually contains that amount) and also for contaminants in the supplement. For example, supplements may be found to contain unacceptable amounts of lead, which is a health hazard, especially to children.

Bottom Line

Choose food first and, supplement, only as needed.

1. Kawasaki B, Hurt E, Mistree T, Farrar W.
Targeting cancer stem cells with phytochemicals.
Mol Interv. 8(4):174 – 184, 2008.
2. Kreider R, Rasmussen C, Melton C, et al.
Long-term creatine supplementation does not
adversely affect clinical markers of health.
Proceedings of the American College of Sports
Medicine 2000 Annual Scientific Meeting; 2000
May 31 – June 3: Indianapolis (IN).
3. Lin J, Cook N, Albert C, Zaharris E, Gaziano
M, Buring J, Manson J. Vitamins C and E and
Beta Carotene Supplementation and Cancer
Risk: A Randomized Controlled Trial. J Natl
Cancer Inst. 101:14 – 23, 2009.
4. Market Research Web site (Internet). North
Adams (MA): Market Research; (Retrieved
2009, May 1). Available from: http://www.
5. Nishino H, Murakoshi M, Mou X, Wada S,
Masuda M, Ohsaka Y, Satomi Y,
6. Jinno K. Cancer prevention by
phytochemicals. Oncology. 1:38 – 40, 2005.
7. Parry GJ, Bredesen DE. Sensory neuropathy
with low-dose pyridoxine. Neurology. 35:1466 –
1468, 1985.
8. U.S. Pharmacopeia Web site (Internet).
Rockville (MD): U.S. Pharmacopeia; (Retrieved
2009, May 1). Available from: http://www.usp.

CLA- Conjugated Linoleic Acid

CLA is a supplement I myself use only because its derived from Safflower Oil (which you can find at your local grocery store) and it helps to actually reduce body fat and help increase lean muscle mass. I have used it and have seen results. Just know that this product might not work for everyone.

CLA can be found in dairy and meats. It is unique because it comes from animal food sources and its anti-cancer efficacy is at concentrations close to human consumption levels. It is found in whole milk, butter, beef, and lamb.

Here are a list of some of the health benefits:

  1. Increases metabolic rate
  2. Decreases abdominal fat
  3. Enhances muscle growth
  4. Lowers cholesterol and triglycerides
  5. Lowers insulin resistance
  6. Reduces food-induced allergic reactions
  7. Enhances immune system

The brand of CLA that I purchase is from GNC:

If you have any questions about it feel free to ask me. I only take this and protein after workouts!! I like my results!

This is me a month after taking CLA:

I know a lot of people who use Creatine and claim that it works without actually doing much research on the supplements that they are putting into their body. Some may not know what Creatine is but I’m here to shed some light on Creatine usage.

Creatine is composed of 3 amino acids: Arginine, Glycine, and Methionine. All 3 of these amino acids are produced in the body and it is mostly found in your muscles. Creatine works to: Increase your creatine phosphate system, Hydrate your muscles, and Increases the reparation process of bodybuilding. Our muscle fibers store ATP (adenosine triphosphate) and that helps you to contract a muscle for about 3 seconds. ATP is only designed for a quick burst and is not used for long term endurance.

Creatine allows your body to hold water which makes all the hardwork you have been putting into the gym show to the world yelling, “LOOK AT ME! I HAVE MUSCLES!” (lol) IF YOU DON’T WORKOUT AND YOU ARE TAKING CREATINE IT WILL NOT HELP YOU BUILD MUSCLE OR LOSE FAT!!!


  1. Muscle volumizing: This is due to all of the water intake causing the muscles to inflate with water
  2. Dehydration: This is caused by large quantities of creatine just sitting in your intestines. To avoid this switch to: creatine monohydrate.
  3. Flatulence aka FARTING: Caused by the large amounts of sugar that are consumed with creatine. Your intestinal bacteria decomposes the sugar releasing gas
  4. Muscle strains, cramps and tears
  5. Renal (kidney) stress


  1. FISH- provides you with a good amount of Methionine. Sushi and Sashimi are PRIME NATURAL SOURCES of creatine
  2. YOUR BODY!!

I myself don’t use creatine. I do take a protein supplement from time to time but the best way to obtain desired results and hold on to them longer is to: NOT USE SUPPLEMENTS!! It may take longer to achieve the results you want but they will last LONGER.