Protein consumption is not an exact science. Recommendations for how much protein an athlete needs can vary from as little as 15 to 20 percent of total calories consumed to as much as 2.2 to 3.3 grams per kilogram of body weight.
By taking into account a few variables, you should be able to narrow down how much protein you need each day.
1. Body Weight
An athlete's weight is the most important variable. A 300-pound offensive linemen's protein needs are vastly different from those of a 180-pound defensive back's. A good baseline measurement is the National Strength and Conditioning Association's recommendation of 1.5 to 2.0 grams of protein per kilogram of body weight.
2. Activity Level
Athletes who are more active require more calories and thus more protein. Two athletes can weigh the same, but if one trains three hours a week and the other 10 hours, they require different amounts of protein to recover and repair their bodies. Also, athletes who do primary resistance training in the off-season need extra protein to allow their muscles to repair and get stronger. Thus, basing protein consumption solely on body weight may not be enough.
3. Protein Quality
The two primary measures of protein quality are biological value and protein digestibility corrected amino acid score. Both of these assess protein based on how well the body absorbs and uses it in the food being consumed. Foods that score high on both measures include eggs, dairy and meat. Plant-based protein sources such as beans and quinoa tend to be lower on these scales. If you consume primary protein on the high end of these scales, you may not need as much protein per day as someone who gets protein mainly from plant-based sources.
Athletes who are very active should aim for the higher end of the NSCA range, as should athletes who consume mainly lower-quality protein.
One more point to take into account is how you feel and perform. Athletes who consume insufficient amounts of protein often feel sluggish, lose strength and do not recover from training sessions as fast as they should. If you feel any of these symptoms, it is a good idea to increase the amount of protein you consume each day.
Baechle, T. (2008). Essentials of Strength Training and Conditioning (3rd ed., p. 208). Champaign, IL: Human Kinetics.
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