Dietary Protein: How Much, Which Sources, and When

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.

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.

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.

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

Athletes who train and compete for multiple hours each day in endurance activities also have extra protein needs. Not because they’re building big muscles. Instead, endurance athletes need extra protein because they tend to consume more protein (amino acids) to power their activity. Whereas the typical athlete gets about 10% of their energy from amino acids, the endurance athlete might get up to 20%. These amino acids come from proteins in the body, such as muscle proteins. These proteins need to be re-built during recovery. Additional dietary protein can be beneficial. How much more? These high-endurance athletes might benefit from consuming 50% more than the amount needed by non-athletes of the same weight.

There are two ways to calculate the daily protein needs of high-endurance athletes:

1) grams of dietary protein calculated above assuming a typical activity X 1.5 = _________

2) _____________________ X 0.56 = _______________ grams of dietary protein daily

Some athletes are engaged in sports that include both endurance and muscle-building components. These athletes might compete in basketball, football, hockey, and soccer. The recommendation is that their dietary protein needs are in-between those of the endurance and muscle-building athletes. They are recommended to consume 75% more than the amount needed by non-athletes of the same weight.

There are two ways to calculate the daily protein needs of athletes with both endurance and muscle-building components:

1) grams of dietary protein calculated above assuming a typical activity X 1.75 = ________

2) _____________________ X 0.65 = _______________ grams of dietary protein daily

Athletes who train more than one hour each day may benefit from more protein than the typical non-athlete. But, it’s worth restating that there has never, ever been a credible study that suggested that any athlete would benefit from consuming more than twice the RDA for non-athletes. Any athlete who consumes 0.74 grams of protein per pound daily can be 100% absolutely certain that his maximum protein needs are being met.

There is absolutely no benefit from consuming excess protein. The excess protein is merely converted to fat and glucose. Fortunately, there doesn’t seem to be any serious harm - at least not in healthy individuals. People with liver or kidney problems might have difficulty processing the excess protein and should be cautious. A diet that has excessive protein requires more urine production. Before protein can be used for energy, the protein’s nitrogen must be removed and excreted. The nitrogen is converted to urea for excretion in the urine. The additional urine may exacerbate hydration challenges. There is also evidence that there is increased loss of calcium in the urine of people on a high protein diet, which can weaken bones over time. For most athletes, the worst consequence of consuming a high protein diet is that they are not able to consume enough carbohydrates. Each bite of excess protein could have been a bite of carbohydrates, the muscles’ preferred energy source. So, their energy level may suffer.

All natural foods contain protein. This fact is often overlooked by most athletes and practically everyone else, including many nutritionists. The few things we eat that lack protein have been manufactured or isolated from natural foods. A couple examples include table sugar isolated from fruit, butter from milk, and oil from corn. But, these are relatively rare. The many thousands of other foods we eat contain protein. Why is this so important?

It is important that you know all foods have protein so you can be freed from the athlete’s obsessive quest for protein. Protein is easy to find. It’s everywhere. Most of us have been taught that athletes need a lot of protein. That’s why we just calculated (above) how much protein we need to eat every day. But, unfortunately, we have not been taught how to properly estimate the amount of protein we get from our diets.

Many of us think we only get protein from foods like tuna fish, chicken breast, eggs, and soy beans. We have been taught that these are protein foods. We recognize other foods as being carbohydrate foods. Sometimes we think we may not be eating enough of these ‘protein foods’ so we take protein supplements. The fact is that it’s relatively easy to get enough protein with natural foods.

The first step toward freedom from the shackles of protein obsession is to stop thinking of foods as protein foods or carbohydrate foods. Instead, think of foods as being protein-rich and carbohydrate-rich. This small semantic shift should cause a seismic rumble in the way you eat.

Open your eyes to see how much protein you’re getting from carbohydrate-rich foods. Let me use a simplified example to demonstrate. We estimated above that a 160 lb soccer player should eat 104 grams of protein to be absolutely certain she’s getting enough. She should also be eating about 450 grams of carbohydrates daily.² Keeping it simple, let’s say she get all her carbohydrates from pasta. That pasta would also contains 90 grams of protein.³ This is a lion’s share of the 104 grams that are needed. Most of us don’t live on pasta alone, but this example demonstrates the significant contribution by carbohydrate-rich foods to our need for protein. This is generally true for most of our carbohydrate-rich foods, such as other food products made from wheat (bread, bagels, waffles), rice, oats, and corn. Naturally, this includes most breakfast cereals and breakfast bars too.

One archaic reason that the dietary protein in carbohydrate-rich foods has been dissed relates to protein quality. The protein quality of carbohydrate-rich foods is not terrific, especially for young children; but neither is it terrible. I’ll try to explain. Remember: All foods contain proteins. All plants and animals contain proteins. These proteins performed important functions for the plants and animals when they were alive. There are thousands of different proteins, each with a unique size and shape. The size and shape of a protein is determined by how the protein is constructed from its constituent amino acids. Some proteins are found in all plants and animals. Some proteins are unique to specific plants or animals. We digest the proteins in plant and animal foods into their amino acid building blocks. We then use these amino acids to build our own proteins. Foods with proteins that are structurally similar to our proteins will yield a perfect mixture of amino acids. We simply digest protein xyz in food and build our own protein xyz. All the food protein’s amino acids are reused completely. If we digest food protein zzz and want to make our protein xyz, then there will be waste. Protein quality refers to how closely the amino acid structure of a food matches what we need to make our own proteins.

The structures and functions of the proteins in animals are very close to those of humans. Consequently, the proteins in foods of animal origin have amino acids that are a close match to ours. It’s a rather simplified way of looking at it, but it’s true. Animal-derived foods generally have high protein quality. They also tend to have higher protein content. For example, the protein quality of whole cow’s milk, pork, chicken breast, and eggs are 100%. The protein quality of beef sirloin is 100% and ground beef hamburger is 93%. The most common protein source used in commercial protein supplements for athletes is whey (isolated from cow’s milk), which has a protein quality of 100%.

While some of the proteins in plants have a similar structure and function as ours, many plant proteins differ from ours quite a bit. The amino acid composition of plant food proteins does not closely match ours. There will be some waste. While plant-derived foods have relatively low protein quality, they don’t have zero protein. Just because it’s not perfect protein does not mean it’s worthless. For example, for pre-school children, the protein quality of oatmeal is 67%, of corn is 48%, of wheat is 38%, of soybean protein isolate is 97%, and of black beans is 100%,. However, for teenagers and adults, the protein quality of these foods is 100%.

Since the amino acid building blocks are not stored in our body very well, it is optimal to consume small amounts of protein throughout the day. Five or six small meals per day would be optimal. Since this is often impractical, including a protein supplement as a between-meals snack might be beneficial. About 10 grams is all that’s useful. However, I prefer something like a serving of non-fat yogurt, which contains about 10 grams of protein and also has a sufficient supply of the other nutrients to support the body’s use of the protein.

Athletes who train more than one hour each day may benefit from more protein than the typical non-athlete. A high protein diet provides no benefits, but can cause problems. A high carbohydrate diet that is moderate in protein is optimal for nearly everyone, especially competitive athletes.

¹ A healthy 150 lb male typically has about 30 lb of protein, most of which is in muscle tissue. About two percent of the body’s proteins are dismantled each day, and need to be simultaneously replaced with new protein. Thus, about 250 grams of protein (about a half-pound) is dismantled to amino acids each day, and 80% (or 200 grams) can be reused; the remaining 50 grams of amino acids need to be consumed in the diet. Therefore, a typical 150 pound male need to eat 50 grams of dietary protein per day (0.33 gm/lb). To be safe, he is advised to eat 56 grams. The RDA is 0.37 grams of protein per pound. This amount is the same for men and women.

² Athletes vary a lot in the amount of calories they need to maintain bodyweight. But a 160 lb woman soccer player might need 3,000 Calories daily during the competition season. A proper diet would provide at least 60% of those calories from carbohydrates: 450 grams (3,000 C X 60% = 1800 Calories; carbohydrates have 4 Calories per gram; 1800 C ÷ 4 C/gm = 450 grams). The remainder of the diet should ~15% of Calories from protein and ~25% of Calories from fat.

³ A typical 1 cup serving of pasta will have about 35 grams of carbohydrate and 7 grams of protein. To consume 450 grams of carbohydrate, you need to consume ~13 servings (450 ÷ 35 = 12.85). This would contain ~90 grams of protein (12.85 servings X 7 grams of protein per serving = 90 grams of protein).

⁴ Protein qualities were estimated using the amino acid scoring method and the data from the online USDA National Nutrient Database and ‘Energy and protein requirements’, a Joint FAO/WHO/UNU Expert Special Technical Report Series 724 to the World Health Organization, 1985. Briefly, a comparison was made between the essential amino acid composition of the food protein and the composition of an “ideal” protein source recommended for teenagers/adults. Teenager/adult reference values are used rather than children’s reference values (used by the FDA and USDA in their estimates of protein quality) since this book is intended for teenager/adult athletes. Therefore, these protein quality estimates would overestimate the quality of these proteins for young children. The highest quality for any food protein is 100%.

Comments (4)

you are recommended to get 54 grams each day

Dear Dr. Dennis Bobilya,
I'm an woman of 24 years. My weight is 150 pounds. I'm doing a 35 minutes exercise which include a 20 minute cardio exercise, a 15 minute lean muscle building exercise. I'm a student and sometimes i have a walk for 30 minutes on 2 days per week. But i'm not sure how much protein should i consume. Please help me and give me the correct amount of protein which i must consume on a daily basis. Thanks...

Thanks for your comment.

The daily protein needs are calculated in grams rather than ounces because the amount of protein in food is always indicated on the Nutrition Facts labels in grams, not ounces. For example, the Nutrition Facts label on my Stonyfield yogurt smoothie reports that one serving contains 10 grams of protein.

Thanks for raising this important point.

USA uses ounces not grams... drop or convert the grams to ozs

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