Mary was a business major who enrolled in my sports nutrition course at the University of New Hampshire. She played on the women’s lacrosse team and was working toward a minor in Nutrition. She always attended class and participated in class discussions. So, I was surprised when she emailed me the following message while conducting research for an essay on the protein requirements of athletes:

Hi Dr B,
Two internet sources I have looked at regarding protein intake for muscle builders have suggested a MINIMUM of 1-1.5 g (preferably 2) for every POUND. That is a ridiculous amount, and I am not sure if these sites have mixed up kg with lbs? They just seem like they know what they are talking about because they give examples. I am confused...

Mary’s not alone in her confusion. Many internet sites are incorrect and spread misleading information, especially when they’re linked to sites that sell protein supplements. I prefer to think that the authors are naively spreading the manure of their own ignorance (like, mixing up kg with lb), rather than lying to sell products and rob athletes.

Why we need dietary protein, briefly.

We eat dietary protein so we can build our own proteins. The proteins in our food are disassembled into their component building blocks (amino acids) during digestion in our stomach and intestine. Then, these amino acids are absorbed into the bloodstream and used by our body to build new proteins. These body proteins perform a variety of specific functions. For example, some proteins in our body function as catalysts for the many reactions that are necessary to support life. Other proteins are the structural foundation of our bodies’ cells. All cells have proteins. Muscle cells are especially rich in proteins, where they provide size and strength. When proteins get old or damaged, the cells degrade them. We need to continuously make new body proteins (including new structural proteins in muscles) to replace those proteins that have been worn out or damaged. When proteins in our cells are degraded, the amino acid building blocks are released and most can be reused to make new proteins. This protein turnover in our cells is constantly occurring. Some amino acids cannot be reused, for a variety of reasons. These amino acids need to be replaced with amino acids acquired in dietary protein. Additionally, a small amount of amino acids are used for energy (~10% of the bodies energy needs is met by ‘burning’ amino acids). A typical adult human needs about 60 grams of dietary protein daily to maintain healthy protein balance. Some athletes may need even more than 60 grams.

How much protein?

Muscles are where most of body’s protein is located, and larger muscles require more protein. Therefore, recommendations for protein intake depend on the size of the individual, usually presented as grams of protein per pound of bodyweight. A lot of scientific research was performed to arrive at a recommendation. This is referred to as the Recommended Dietary Allowance (RDA). The RDA is a conservative recommendation that is considered sufficient for nearly everyone (98% of the population), including most amateur athletes. The RDA is 0.37 grams of protein per pound.¹ If everyone ate 0.37 grams of protein per pound daily, then 98% of us would get more than enough protein. This amount is the same for men and women.

Calculate your recommended daily protein intake now:

_____________________ X 0.37 = _______________ grams of dietary protein daily

(Your weight in pound)

Example:

160 lb of bodyweight X 0.37 = 59 grams of dietary protein daily

Size is not the only factor that influences a person’s need for dietary protein. A person’s physical activity level is also important. The calculation above is for people of ‘average’ activity – non-athletes and athletes off-season or during light training. This includes people who exercise moderately for up to an hour each day. Athletes engaged in activity that is intensive or lengthy may need extra protein.

Research has demonstrated that athletes who train intensively to increase muscle size and strength may need up to twice the protein needed by a non-athlete. The additional protein is needed because these athletes are increasing the size of their muscles, which are high in protein. In a sense, the body is accumulating protein. This is especially true during the first six weeks of a muscle-building program. Athletes who use muscle-building steroid hormones also would need extra protein. Muscle-bound athletes who have a higher than typical muscle mass in their bodies would also need extra dietary protein. How much more? These muscle-building and muscle-bound athletes might benefit from consuming up to twice the amount needed by non-athletes of the same weight. There has never, ever been a credible study that suggested more than double would be beneficial for a non-athlete. So, if you consume this amount of protein daily, you can be 100% absolutely certain that your maximum protein needs are being met.

There are two ways to calculate the daily protein needs of muscle-building and muscle-bound athletes:

1) grams of dietary protein calculated above assuming a typical activity X 2 = _________

2) _____________________ X 0.74 = _______________ grams of dietary protein daily

(Your weight in pound)

Example:

200 lb of bodyweight X 0.74 = 148 grams of dietary protein daily