In this series, ACE experts answer your health and exercise questions. From nutrition to exercise programming, you’ll find detailed answers to many of the questions that may come up in your work with clients. If you have questions you’d like to ask our experts, please email us at Christine.Ekeroth@acefitness.org.

The Expert: Steve Farrell, PhD, FACSM. Dr. Farrell recently retired after a 41-year career at The Cooper Institute in Dallas, Texas. He earned his doctorate degree in exercise physiology with a secondary emphasis in nutrition from Texas Woman’s University. His master’s and bachelor’s degrees were earned at the University of South Carolina and Springfield College, respectively. Farrell spent most of his career at Cooper in the Education Division, where he and his colleagues taught a variety of health and fitness workshops to tens of thousands of students, with a heavy emphasis on training fitness leaders in public safety and all branches of the U.S. military. Under his direction, The Cooper Institute became one of the first organizations to receive national accreditation for their Personal Trainer Certification in 2006. Farrell also served as a consultant for the National Health and Nutrition Examination Survey (NHANES). The latter portion of his career was spent in the Research Division, where he published numerous papers from the Cooper Center Longitudinal Study (CCLS) data base. He has been a frequent presenter at the national meeting of the American College of Sports Medicine.

Q: There are so many opinions about how much protein people need and I’m starting to feel as confused as my clients! Are there any health issues or signs someone might look for if they aren’t getting enough protein in their diet? And is there an easy way to make sure you get enough protein without having to weigh your food or count every calorie?

A: Without a doubt, this is an important question that health and exercise professionals frequently encounter from clients. Before we dive into the answer, I feel it would be helpful to provide some background information regarding dietary protein. In fact, you might consider passing some of this info on to your clients who have an interest in the topic. First, protein is one of six essential nutrients required by the human body for survival. Composed of highly complex chains of tiny building blocks called amino acids, dietary protein is broken down into these amino acids during the digestive process and then transported across the intestinal wall and into the bloodstream. These individual amino acids serve many important functions, including the repair and growth of cells as well as serving as the structure of hemoglobin, enzymes, antibodies, and some hormones. Additionally, a few of the amino acids serve as a minor source of fuel for energy. This is especially true during long-term endurance exercise.

The current Recommended Dietary Allowance (RDA) for protein is 0.36 grams per pound of body weight per day for normal/apparently healthy adults. So, a client weighing 150 pounds would require 150 x 0.36 = 54 grams of protein per day. For comparative purposes, the average U.S. adult male and female consumes 97 and 69 grams of protein per day, respectively. It’s important to note that if your client is an endurance athlete or a strength athlete, then the recommended protein intake is higher than the RDA. Current guidelines state that endurance athletes should strive for approximately 0.6 grams of protein per pound of body weight per day, while strength athletes may require as much as 0.9 grams per pound of body weight per day. Additionally, dietary protein needs are increased during pregnancy; the current RDA for women during pregnancy is 0.5 grams per pound of body weight per day. 

There is no shortage of protein in the American diet, as protein is abundantly available in a variety of food sources. These include dairy, eggs, meat, poultry, fish and soy products, which are known as complete proteins. A complete protein contains all nine essential amino acids that are required for survival. However, there are many other great plant-based sources of protein. These are known as incomplete proteins because they are deficient in one or more of the essential amino acids. Incomplete proteins include nuts and seeds, grains, green vegetables and legumes (beans and peas). These incomplete proteins can be combined in many ways to yield a complete protein. For example, beans and rice yield a complete protein, as does a peanut butter sandwich. Because protein is so easy to find in everyday food, there is seldom a situation where protein/amino supplements are necessary. 

While dietary protein deficiency is relatively uncommon in the U.S., it can occur among individuals with eating disorders, as well as among individuals with inflammatory bowel disease or chronic kidney disease (CKD). Signs of protein deficiency can include hair loss, edema and slow wound healing. A low blood albumin level can provide an objective measure of protein deficiency. If your client is concerned that they are not getting adequate dietary protein, consider referring them to a healthcare professional for this simple blood test.

No one wants to have to constantly weigh their food or count every calorie. Once you have calculated your clients’ estimated daily protein requirement, review Table 1 with them to illustrate what kinds and quantities of food they need to consume each day in order to meet their protein needs. Note that this table does not include all dietary protein sources. As a health and exercise professional, you might consider obtaining some plastic food models so you can show your clients exactly what 4 ounces of fish, 1 cup of cooked pasta, etc., looks like.

Table 1. Common Sources of Protein

* Note that almond milk and rice milk typically contain only about 1 gram of protein per cup.

Here’s an example of how to meet protein needs using the client we mentioned above who requires about 54 grams of protein per day. Keep in mind that the client will be consuming other foods during the day as well; we’re just focusing on significant sources of protein (Table 2).

Table 2. Sample Daily Protein Intake

Q: Many of my clients are moving toward adopting a vegetarian or vegan diet and they’re concerned about making sure they get enough protein to maintain their muscle mass. Can you recommend the plant-based foods with the highest-quality protein and offer tips on how they can make sure they’re getting enough to meet their needs?

A: First, let’s be sure we all understand the difference between vegetarian and vegan diets. Vegetarians do not consume animal flesh (meat, fish, shellfish, poultry), but do consume dairy products and eggs. A vegan diet is much stricter, as vegans do not consume any products derived from animals.

As mentioned previously, there are many great sources of protein that come from plant-based foods. These include nuts and seeds, grains, green vegetables, soy products and legumes. So, for a vegetarian client, it should still be very easy to meet daily protein requirements and maintain muscle mass without having to resort to amino acid/protein supplements. For a strict vegan client, it will be more of a challenge, particularly if they are an athlete. Recall that endurance and strength athletes may require as much as 0.6 and 0.9 grams of protein per pound of body weight per day, respectively.

Here's an example for a 120-pound female who participates in endurance events and follows a vegetarian eating plan. She will require 120 x 0.6 = 72 grams of protein per day. Remember that this client will not consume meat, fish or poultry. In addition to the foods listed in Table 3, she will be consuming other foods during the day as well.

Table 3. Sample Protein Intake for a Vegetarian

If this same client happened to be a strength athlete, she might require as much as 120 x 0.9 = 108 grams of protein per day. In that case, you might suggest that she add two hard-boiled eggs, a 3.5 ounce serving of tofu, an additional 0.5 ounces of nuts, and a cup of reduced-fat ice cream to the items listed in Table 3.

Q: I’ve heard that people who are taking the GLP-1 medications need to be sure to eat enough protein. Is this true? And how can they be sure to do that when their overall calorie intake is fairly low?

A: First, let’s review a bit of background information regarding these medications. Broadly, they go by a few different names, including GLP-1 agonists, GLP-1 receptor agonists and GLP-1 analogs. While several GLP-1 drugs are available in the U.S. market, the one that you and your clients have most likely heard of is semaglutide (Ozempic).

The FDA approved the first GLP-1 in 2005, specifically for the treatment of type 2 diabetes. Diabetes is characterized by abnormally high blood glucose levels, which, if left unchecked long-term, results in devastating health consequences, including blood vessel and nerve damage, heart attack, stroke, blindness and amputations. GLP-1 drugs reduce blood glucose levels by decreasing appetite, slowing gastric emptying, increasing insulin production and decreasing glucagon production by the pancreas. This is especially true when regular physical activity and a prudent diet are incorporated into the patient's lifestyle. Most individuals with type 2 diabetes have overweight or obesity. During the clinical trials for GLP-1 drugs, the very favorable side effect of significant weight loss was noted, with an average loss of 5 to 10% of body weight. Thus, there has been a huge a demand for these medications in recent years, not only from the estimated 36 million U.S. adults with type 2 diabetes, but also for the millions who struggle with obesity. As you’ve probably heard, demand for these drugs continues to exceed supply.

It is worth noting that the overwhelming majority of published studies that report on weight loss make no distinction between loss of lean mass versus loss of fat mass. In the few GLP-1 clinical trials that measured changes in lean mass, it was observed that patients lost an average of 10% of their muscle mass during an average intervention of 70 weeks. Obviously, you want your clients who are taking GLP-1 drugs to minimize loss of muscle mass and maximize loss of fat mass. A recent paper addressed these concerns. The authors emphasized the importance of meeting the protein RDA by including high-quality protein (i.e., complete proteins). Because caloric restriction is part of the treatment plan for weight loss, and because appetite is diminished in patients taking GLP-1 drugs, the authors also suggested that an oral protein supplement may be needed. The importance of regular resistance training (i.e., meeting current guidelines of at least two total-body workouts per week) for maintaining muscle mass was also emphasized in the paper.

Because patients with diabetes who are taking GLP-1 drugs represent a special population, and because the scope of practice for health and exercise professionals, does not include prescribing specific diets to clients, a Certified Diabetes Educator or registered dietitian nutritionist should be part of the patient's care team.

Q: I have a client who drinks protein shakes multiple times per day. I’m concerned they might be consuming too much protein, but is that even possible? What are the risks of overconsumption?

A: Three keys to healthful eating include variety, balance and moderation. It should be easy to see that drinking multiple protein shakes on a daily basis violates all three of these principles. Protein is just one of the six essential nutrients, so consuming multiple protein shakes each day may well lead to insufficient intake of other essential nutrients. Depending on what kind and how much of other nutrients are present in the shakes, deficiencies may occur long-term. For example, if the shakes do not contain any fiber, then constipation or diverticulitis (inflammation of the intestines) may occur. If the vitamin and mineral content of the shakes is low, then deficiencies of these essential micronutrients may show up down the road. So again, the main concern is that there may be a lack of other essential nutrients in a diet that leans much too heavily on protein shakes.

For many years, the notion that too much dietary protein could damage the kidneys was considered a myth. More recently, evidence has come to light that long-term excessive protein intake (particularly animal protein) may indeed predispose some individuals to chronic kidney disease (CKD). Extra dietary protein is converted to glucose and fatty acids, a process that occurs primarily in the liver. While this conversion itself is relatively innocuous, there is evidence that an excessive dietary protein load can cause hypertension within the kidneys, and potentially lead to CKD. Clients with existing CKD who are not on dialysis are strongly advised to limit their protein intake since excessive protein can cause further deterioration of kidney function. For a client with CKD who is on dialysis, an increase in protein is recommended since some blood proteins are lost during the procedure. In terms of dietary programming, clients with CKD should be working closely with a registered/licensed dietitian nutritionist or other qualified health professional, regardless of whether or not they are on dialysis.   

So, the bottom line is that the recommended maximal amount of daily protein is 0.6 grams per pound of body weight for endurance athletes and 0.9 grams per pound of body weight for strength athletes, assuming normal kidney function is present. For your clients who are not athletes and just want to be healthy, the RDA of 0.36 grams per pound of body weight should suffice. As an aside, kidney function is easily measured with blood and urine tests. In conclusion, while protein is an essential nutrient, more is not necessarily better. Your client can get too much of a good thing!

Expand Your Knowledge

Applying Nutrition Principles – Course Bundle

As an exercise professional or health coach, it is important to remain within the scope of your practice when coaching nutrition and better nutrition choices to your clients. The Applying Nutrition Principles course bundle will equip you with information and meaningful behavior change techniques to help you support your clients in healthier food choices and implement into your practice immediately.

Better Together: Combining Fitness and Nutrition for Powerful Results

This video training explores the individual and combined effects of physical activity and nutrition interventions provided by fitness professionals. You’ll gain knowledge of how to leverage multidisciplinary approaches that establish positive behavior changes in adults and learn how evidence from exercise and nutrition practitioner guidelines align with the ACE IFT^® Model, along the health, fitness and performance spectrums.