Sunday, June 26, 2011

Athlete Protein Intake

Protein Intake:
Are You Getting Enough or Too Much?

It is always difficult to determine how much of a macronutrient (protein, carbohydrates or fat) is OK for your diet plan. What is enough? What is too much? What is considered best based on current research? I wrote this bit on protein on the basis of questions. These are questions that are common in the fitness industry. For the section about the 'client' I used my own personal information. OK, so now you know I am a tiny individual. I was also a professional dancer (athlete) for 15 years and my caloric intake is nothing like it use to be. I hope that you will find this little "study" relate-able. 

1)     How can you determine the protein intake required for an individual.  

There has been quite a bit a research regarding protein and athletic benefit. The Food and Nutrition Board that states that there is little scientific evidence to support that recreational or non-elite athletes consume more than the recommended 0.8 g/kg/d of protein (Venderley & Campbell, 2006). However, this number is constantly contradicted in numerous studies and nutrition literature. Many studies support the consumption of 1.2 – 1.4 g/kg for endurance athletes and 1.6 – 1.7 g/kg for strength athletes (Phillips, Moore & tang, 2007). The International Society of Sports Nutrition recommends 1.0 – 1.6 g/kg determined by activity level for athletes (Fuhrmann & Ferreri, 2009). Some studies have even shown that athletes can consume as much as 3 g/kg safely based on the recommended percentage of protein caloric intake, however, there is limited proof as to any benefit with intakes this high (Phillips et al., 2007). An athlete with a high caloric diet will naturally consume a higher gram rate of protein.

My client is a 38 year old male that weighs 154 lbs (70 kg). His diet runs him up at about 2000 Kcal p/d. He exercises on average ≥60 min per day or 300 min per week. His training includes, but is not limited to, 30-40 min of cardio, stretching, resistance training, agility training, power training and ultimate Frisbee. My client is active for the sole purpose of maintaining health. According to the Centers for Disease Control and Prevention this would place him as an active “recreational” athlete (Laquale, 2009). Since my client is considered a recreational athlete it is recommended that my client consume 15% of his diet in protein (Laquale, 2009). 2000 * .15 = 300 kcal from protein, 300 kcal / 4 kcal = 75 g protein, 75 g / 70 kg = 1.07 g/kg. It would be recommended that my athlete consume 1.07 g/kg of protein per day. As you can see this is above the recommended 0.8 g/kg by the Food and Nutrition Board, but is within the recommended limits of the International Society of Sports Nutrition and within range of the American College of Sports Medicine, American Dietetic Association and the Dieticians of Canada (Venderley & Campbell, 2006).

2)    Consider the same individual- what would your recommendations change based  on the following scenarios:

a) The athlete is a vegan 

There are no major changes that should be made if my client were to be a vegan. Vegans are a type of vegetarian whose diet excludes all animal and animal derived products such as dairy, gelatin, or even honey. They are completely void of any and all meat sources and there is ample evidence that vegans are capable of providing all of their caloric needs through their diets (Venderley & Campbell, 2006). However, plant proteins sometimes are not all completely digested due to their high fiber content, so it would be recommended that they increase their protein intake by 10% (Venderley & Campbell, 2006). This would mean that if my client were to continue consuming 75 g/d of protein he would most likely not benefit from all of the protein consumed. He would then increase his intake by 7.5 g/protein per day (75g * 0.1 = 7.5g). It would be best for my athlete to eat from a variety of plant sources to get their supply of protein. Some great sources for plant proteins are tofu, nuts, seeds and hemp seed meal (Fuhrmann & Ferreri, 2009).  There is plenty of evidence that vegans and other vegetarians are capable of producing ample power, strength and endurance to become elite athletes. Some famous vegetarian athletes are Carl Lewis, Tony Gonzales and Kenneth Williams (Fuhrman & Ferreri, 2010).

Since my client would be missing the animal elements in his diet it would be advisable for him to talk to a dietician about Zinc, Iodine, vitamins B12 and D, Iron, Calcium, Omega-3 fatty acid and Taurine supplementation (Fuhrman & Ferreri, 2009). Creatine might be an issue for the power athlete, since it is found only meat, fish and poultry. The body can produce approximately 1 g/d of creatine (Venderley & Campbell, 2006). This amount might not be enough to satisfy the power athlete, so supplementation of creatine might also be recommended. My athlete does partake in power training (sprints, plymetrics and Tabata training), so it would be advisable for him to supplement with creatine. A dose of 3 g/d has been shown to significantly elevate creatine stores in the muscles of vegetarians (Venderley & Campbell, 2006). Since this amount has been shown to significantly increase creatine concentrations my athlete could consume an even lower dose to just maintain adequate concentrations of creatine within his muscles to help him with his power training.

b) The athlete is in a 500-1000 Calorie per day deficit (ie- the athlete is attempting to lose weight)

Since my athlete is pondering a negative caloric balance of 500 – 1000 kcal per day it would be advisable for my athlete to make sure that they are still getting an adequate amount of all macronutrients. A reduction in caloric intake can compromise the athlete’s endurance and power capabilities (Garthe et al., 2011). It would be advisable for my athlete to not exceed a caloric deficit of 500 kcal. This would put him at a caloric intake of 1500 kcal/d. In a study performed by Garthe et al., (2011) the athletes were placed on a diet that was no lower than 1500 kcal and consisted of 1.2 – 1.8 g/kg of protein, 4 – 6 g/kg of carbohydrates (CHO) and ≤20% from fat. This diet was determined to eliminate a loss of lean body mass and to provide adequate sources of energy for training (Garthe et al., 2011). My client could successfully reduce his calories from fat and CHO. The results of the study showed positive increases in lean body mass and weight loss without reducing power-performance during training. I would recommend my client to follow the protocols set up in this study to reduce his weight while training in a negative caloric balance.    

3)    How would you explain to a strength/power athlete consuming 3 g/Kg of protein per day in a eucaloric state that protein intake of that level does not lead to optimal performance.

Even though there is no evidence that 3 g/kg of protein per day is beneficial to his/her performance, there is also no evidence that 3 g/kg per day will cause detrimental affects to his/her health (Phillips et al., 2007). There is also no clear evidence that quantities larger than 2 g/kg produce benefits (Fuhrmann & Ferreri, 2010). There is also some evidence that states that consuming large quantities of protein can lead to kidney dysfunction, decreased bone health caused by poor calcium stores, and may negatively affect cardiovascular health (Fuhrmann & Ferreri, 2010). This statement is greatly disputed by Phillips et al., (2007) who states that many studies have discarded the last statement through research and trials. So the evidence that high protein diets can be detrimental to the health of an athlete may be invalid and more research should be done to determine what the safest level of protein intake is for an athlete. So far there has not been an upper level limit set for protein by the Food and Nutrition Board, but it is recommended that an athlete limit their protein intake to 35% even though 1.2 – 1.6 g/kg has been shown to be beneficial for all athletes  (Phillips et al., 2007).

A supplement is just that, a supplement. Supplementations should only be used if the athlete is not getting adequate nutrition from their diet. I highly recommend reading the following article to understand the absorption rates of protein in the diet. This is especially important when determining what type of protein supplement might work best for an athlete.

Bilsborough, S. & Mann, N. (2006). A review of issues of dietary protein intake in humans. International Journal of Sports Nutrition and Exercise Metabolism, 16, 129-152.


Fuhrman, J., & Ferreri, D. M. (2010). Fueling the vegetarian (vegan) athlete. Current Sports Medicine Reports, 9(4), 233-241.

Garthe, I., Raastad, T., Refsnes, P. E., Koivisto, A., & Sundgot-Borgen, J. (2011). Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. International Journal of Sport Nutrition and Exercise Metabolism, 27(2), 97-104.

Lanquale, K. (2009). Nutritional needs of the recreational athlete. Athletic Therapy Today, 14(1), 12-15.

Phillips, S. M., Moore, D. R. & Tang, J. E. (2007). A critical examination of dietary protein requirements, benefits, and excesses in athletes. International Journal of Sports Nutrition and Exercise Metabolism, 17, S58-S76.

Venderly, A. M., & Campbell, W. W. (2006), Vegetarian diets nutritional considerations for athletes. Sports Medicine, 36(4), 293-305.

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