Trainers can often be overheard giving their clients dietary advice, such as recommending that they increase their consumption of high protein foods like egg whites, chicken breast, and fish. They may also encourage clients to start purchasing various protein bars and shakes to consume in between meals or in place of meals. Many exercisers and trainers alike believe that in order to build muscle and lean body mass, one must consume large amounts of protein. However, the actual fact is that any protein consumed above and beyond an individual’s needs will be burned as fuel or stored as glycogen or fat. In addition, when a person focuses on a high protein diet, it is quite possible that they will sacrifice carbohydrate intake. This can actually result in a diminished ability to perform and exercise to their potential, because they are lacking adequate amounts of the body’s primary fuel: carbohydrate. In this case, over-consuming protein leads to under-consuming carbohydrates and can prevent the individual from reaching their fitness goals (Clark, 2008).
This article will clarify how much protein exercisers and athletes really need in order to achieve their desired results. Trainers will understand whether or not expensive protein bars, powders, and shakes are worth the investment, or if clients can get the same nutrients and amino acids that they need from a standard diet including lean protein sources two to three times per day.
Functions of Protein
Protein serves many important functions in the body. We learn in school that protein is made up of amino acids – that is why they are often called building blocks. Some of these amino acids are synthesized in the body, while others — called essential amino acids — must be obtained from protein-rich food sources.
It is widely known that protein helps to build and repair muscle tissue. During exercise, muscle is broken down and damaged. Protein is then required to establish a positive protein balance in the body, which allows for muscle repair, synthesis, and hypertrophy. After resistance exercise is done, the body’s muscles can be in synthesis above resting levels for up to 48 hours (Phillips, 2004). During these periods, the body uses protein to support these muscle gains. Other important functions of protein in the body include: replacing red blood cells, serving as antibodies to boost the immune system, growing hair and nails, producing hormones, and facilitating the body’s chemical reactions as enzymes (Clark, 2008).
Populations At Risk for Under-Consuming Protein
Vegetarians may not get as much protein in their diets as non-vegetarians, due to the fact that they do not eat many or any sources of animal protein (Lemon, 1997). However, it is possible for vegetarians to consume adequate protein through vegetarian food sources such as beans, nuts, dairy products (if applicable), and soy products like tofu.
Endurance athletes and intense exercisers need to make sure to consume enough protein to account for the body’s structural needs and building new muscle tissue, in addition to providing small amounts of protein as fuel. Dieters, who are calorie-restricted, may not be consuming enough protein to support both their energy needs and their muscular growth and repair needs. Beginner exercisers may also need more protein to support the body’s new demands for muscle growth. Lastly, individuals who are still growing, like teenagers, need more protein to support their bone and muscle growth and development (Clark, 2008).
Potential Dangers of Over-Consuming Protein
Those consuming high protein diets may be at risk for dehydration. This is because the nitrogen from protein metabolism must be excreted from the body in the urine (as urea), which increases water loss. In addition, exercisers and athletes already have increased fluid needs due to sweating. Therefore, those exercising and following a high protein diet must ensure that they consume adequate amounts of fluid daily, and can monitor this by weighing regularly (Lemon, 1997).
With the intake of purified protein products, it is possible that high protein intake can lead to calcium being excreted in the urine. This may present a problem, since calcium levels in the body are crucial to bone health. When protein is consumed in food sources, the phosphate in the food prevents the calcium from being excreted (Lemon, 1997).
Protein Needs for Various Levels of Exercisers and Athletes
Many studies have shown that strength-trained athletes regularly consume more protein than their bodies require (Phillips, 2004). While it is true that muscles need sufficient protein for hypertrophy, many exercisers think the more protein, the better. Although different types of exercisers and athletes have different protein needs, there has been no scientific evidence that there is any benefit to consuming greater than two grams of protein per kilogram of body weight per day (Clark, 2008). In fact, a study published in 2008 revealed that supplementing men ages 48 to 72 with creatine and/or whey protein did not result in a more improved body composition than with resistance training alone (Eliot, et al., 2008).
Since individuals needs vary, it is difficult to determine the exact protein needs of active people. However, protein recommendations have been defined by leaders in sports nutrition, such as Nancy Clark, the American College of Sports Medicine, and the American Dietetic Association. Overweight or obese individuals should base their protein needs on their ideal body weight versus their actual weight.
To determine ideal body weight, use this formula:
- Women: 100lb (45.5kg) for the first five feet of height plus 5lb (2.3kg) for each additional inch.
- Men: 106lb (48.2kg) of body weight for the first five feet of height plus 6lb (2.7 kg) for each additional inch.
- For a small body frame subtract 10%, for a large frame add 10%.
Protein Recommendations (Clark, 2008)
||Grams of protein/
lb of body weight
|Grams of protein/
kg of body weight
|Recreational exerciser, adult
|Endurance athlete, adult
|Growing teenage athlete
|Adult building muscle mass
|Athlete restricting calories
|Estimated upper requirement for adults
As an example, your client Amy is 30 years old, 5’3” tall, weighs 160lb (72.7kg), and has an average frame. She goes to the gym three times per week and uses the treadmill or elliptical for thirty minutes and takes some sculpting/strength-based classes. Her height and weight put her in the overweight category, according to the BMI (body mass index) scale. Therefore, use her ideal body weight to determine her protein needs. Using the formula above, her ideal body weight is 115lb (52.3kg). Since Amy is a recreational exerciser, multiply her ideal weight of 115lb by 0.5-0.7. Amy’s protein needs are in the range of 57.5 to 80.5 grams of protein per day.
Dietary Sources of Protein
Since most diets in developed countries are abundant in protein, it should not be a challenge for most people, including athletes, to reach their protein requirements through food alone. In general, animal-based foods like meat, poultry, fish, and dairy products are great protein sources. In addition, many vegetarian foods such as beans, tofu/soy, and nuts are high in protein as well.
The following foods have about 7 grams of protein for the portions listed:
- 1oz (30g) chicken, turkey, fish, beef, lamb, or pork
- 1oz (30g) cheese
- ¼ cup (60mL) cottage cheese
- 1 egg or 2 egg whites
- 1 cup (250mL) milk (~8 grams of protein)
- 6oz (180g) regular yogurt
- 3oz (90g) Greek yogurt (twice the protein of regular yogurt)
- ½ veggie burger
- ½ cup (125mL) beans (chickpeas, black beans, kidney beans, etc.)
- 2oz (60g) extra firm tofu
- 1oz (30g) almonds or peanuts (28 nuts)
- 2 tablespoons (30mL) peanut butter
- ½ cup (125mL) hummus
- 1 cup (250mL) split pea or lentil soup (~9 grams of protein)
Using the list above, if Amy had two eggs for breakfast, a turkey sandwich with three ounces of turkey for lunch, a six-ounce Greek 0% fat yogurt for a snack, and four ounces of salmon for dinner, she would have consumed 77 grams of protein from the food noted, which is at the top of her protein requirement range. She actually consumed more than 77 grams of protein because in this example, as the protein in her starches, vegetables, and other various foods were not included.
Let’s take the example of Carl, a 220lb (100kg) bodybuilder, who requires much more protein than Amy. Assuming Carl is not overweight or obese, and using the protein recommendation above for an adult building muscle mass, his protein requirements would be 154 to 176 grams per day (220lb multiplied by 0.7-0.8). Here is an example of how Carl could meet his high protein requirements with food alone:
- Breakfast: 1½ cups (375mL) of low-fat cottage cheese with ¾ cup (175mL) berries
- Snack: apple with two tablespoons (30mL) peanut butter and a glass of skim milk
- Lunch: 6oz (180g) turkey burger topped with 1oz (30g) low-fat cheese
- Snack: whole wheat crackers with ½ cup (125mL) hummus
- Dinner: 6oz (180g) chicken breast with steamed broccoli and ½ cup (125mL) kidney beans
- Total protein: 162 grams (again, this is not including the protein he is getting from starches and vegetables)
With the examples above, it is easy to see that by including high protein foods in most meals and snacks, it is quite simple for an individual to meet their protein needs with food alone. However, many people have a busy lifestyle and prefer to consume products like shakes and bars for their convenience. While many hold on to the belief that supplementing with specific isolated amino acids is optimal, the fact is that this practice is unnecessary. Supplementing with whole protein sources like soy, whey, and casein are very effective for nourishing the skeletal muscle for maintenance and growth. Those who do not eat dairy or animal protein sources, like vegetarians, may benefit from consuming protein in the form of powders and bars. These products can be included in a healthy diet, and in place of real foods in order to achieve adequate protein intake. The important thing to note is that these products are not usually needed in addition to a healthy diet filled with lean and low-fat sources of high-quality protein. Real, whole foods have an advantage over synthetic foods, such as protein shakes and bars, because of the wide variety of naturally occurring vitamins, minerals, and other nutrients in these foods.
- Clark, N. (2008). Nancy Clark’s Sports Nutrition Guidebook, Fourth Edition. Chestnut Hill, MA: Human Kinetics.
- Eliot, K.A., Knehans, A.W., Bemben, D.A., Witten, M.S., Carter, J., & Bemben, M.G. (2008). The effects of creatine and whey protein supplementation on body composition in men aged 48 to 72 years during resistance training. Journal of Nutrition, Health & Aging, 12(3), 208-212.
- Lemon, P. W.R. (1997). Dietary protein requirements in athletes. Journal of Nutritional Biochemistry, 8, 52-60.
- Phillips, S.M. (2004). Protein requirements and supplementation in strength sports. Nutrition, 20 (7/8), 689-695.