Protein and body composition enhancement go hand-in-hand like peanut butter and jelly, movies and popcorn, false hope and the Chicago Cubs, or Samuel L. Jackson and mother******. It’s probably safe to assume that if you lift weights (regardless of what your goals are), you eat protein. Specifically, you eat lots of dead, cute, and furry animals. That being said, I am also going to assume that many of you reading this article are still curious to know the basics. Why else would you click on an article about protein, right?
What is it? What are the different types? What are its roles? When are the ideal times to ingest it?
How do dietary requirements differ between individuals who are trying to shed body fat as compared to those who or trying to add mass or who are involved in athletics? How is it metabolized? Will it help you get chicks? All are very prudent questions when discussing the topic of protein. So instead of me extending this introduction any further, why don’t we get right to it, eh?
“Eat all the protein you want. You will NEVER have a chance with a hot lady.”
Actually I Lied
Before I get into the meat (no pun intended) and potatoes, I want to preface all of this by saying that I did write a rather lengthy article not too long on the topic of carbohydrates. (The Carbohydrate Conundrum) If you actually read the entire thing, give yourself a medal. I know it wasn’t an easy read. In spite of that, I believe I was able to shed some light on this very “murky” topic and help to dispel a lot of the myths that are prevalent. When it comes to protein however, I feel that it’s not such a black and white debate, so I will spare you the novel. Everyone who is involved with training and/or athletics knows that dietary protein plays a major role in improved body composition (as well as several other key roles discussed later). Nevertheless, I feel that there are many people out there who may still be confused on the matter. As with carbohydrates, there is a major difference between NEED and OPTIMIZATION and I hope the information provided in this article will help to differentiate between the two.
The Basics (AKA…The Boring Stuff)
The word protein comes from the Greek word prota meaning “of primary importance,” which is meant to indicate its main role in human nutrition. [It’s also meant to give you the opportunity to impress your friends with your vast array of useless knowledge.] One key difference from carbohydrate and fat, which contain only carbon, hydrogen, and oxygen atoms, is that proteins contain nitrogen atoms. These nitrogen atoms give the name amino (“nitrogen containing”) to the amino acids of which protein is made. Amino acids are the molecules that, when joined in groups of a few dozen to hundreds, form the thousands of proteins occurring in nature.
There are 20 amino acids that occur in the diet. More than half of these can be synthesized by the human body and are commonly called non-essential amino acids because they DO NOT need to be consumed in the diet (the body can make them on its own from other sources). Nine of the amino acids are essential because the body cannot manufacture them and they must be consumed through the diet.
Essential and Non Essential Amino Acids
Sources of Protein
Protein can basically be divided into two main categories, complete and incomplete sources. Complete sources of protein are those found from animals:
Animal Sources: if it swims, flys, or has four legs and is furry…it’s a great source of protein. Additionally, eggs and cottage cheese and various other dairy products would fall under this category as well.
Incomplete proteins are those found in plants, and include:
- Plant Sources: beans (kidney, garbanzo, etc), soy, chickpeas, tofu, lentils, and a variety of whole grains (muesli, wheat, etc).
- Protein Powders: these get their own category because it’s my article and I said so! Technically speaking, protein powders are more often than not derived from whey, which is the by-product of cheese manufactured from cow’s milk.
However, there are also protein powders made from peas, eggs, soy, and a host of other sources, which become more of a factor for those with specific food allergies (such as milk). But to keep things simple, let’s keep the discussion on whey protein and its variations.
- Whey Protein Concentrate: contain fat, lactose, cholesterol, carbohydrates, and other bioactive compounds.
- Whey Protein Isolate: are processed to remove the fat, lactose, and carbohydrates, and is typically more expensive.
- Whey Hydrolysate (hydrolyzed whey): “broken down” whey proteins which are absorbed by the body more quickly and are typically the most expensive.
Note – Protein powders are ideal for Post-Training because the body absorbs them so quickly.
Interestingly, protein that comes from animals is considered to have a higher Biological Value (or quality) compared to those that come from plant sources. Biological Value (BV) is a value that measures how well the body can absorb and utilize a protein. The higher the Biological Value of the protein you use, the more nitrogen your body can absorb, use, and retain. Since protein is used in the construction of bodily cells the more protein that is retained indicates a higher level of biological utilization of the particular protein. The more nitrogen that is excreted as urine and fecal matter, the less utilizable the particular kind of protein.
Biological Value of some Common Protein Sources
And BV is Relevant Because?
I’ll take this opportunity to briefly discuss vegetarian diets. While I will be the first to admit that there are MANY vegetarians out there who thrive on not eating animal protein, I also know that there are even more who shoot themselves in the foot from a body compositional standpoint by leading such a lifestyle. Many people are under the impression that all animal protein is fattening and will result in high cholesterol levels and clogged arteries. As a result, their only sources of protein come from plants. While this rationale does have SOME merit, it’s all together untrue. If one is cognizant of choosing LEAN sources of protein (lean beef, chicken breast, turkey, tuna, egg whites, 1% cottage cheese, protein powders, and a host of other sources), this is a non-issue in my opinion
In the book “Nutrient Timing,” co-author Dr. John Berardi briefly discusses the downfalls of a vegetarian diet. He points out that there have been numerous studies which have demonstrated that a lacto-ovo-vegetarian diet (dairy and eggs allowed) can interfere with the positive body composition changes seen in meat-eating weight trainers. In one particular study, it was shown that after twelve weeks of training, the meat-eating group lost about 2.9 pounds of fat while gaining 3.7 pounds of lean mass. However, the vegetarian group gained about 0.2 pound of fat and LOST about 2.4 pounds of muscle. And to think that this was WITH dairy and eggs allowed. I can only imagine what happens with “true” vegetarian diets.
Again, I want to reiterate that I know there are many vegetarians out there who have very impressive physiques and lead very athletic lives despite not eating any animal proteins. But I think that they are few and far between. In the end, it’s been consistently shown that diets containing animal proteins (therefore diets with a higher BV value), in conjunction with resistance training, tend to increase lean muscle mass and prevent LBM loss compared to vegetarian diets. It’s also been shown that people who eat animal proteins don’t look like weak, emaciated underwear models, but I digress.
Kind of hard to argue with science, although I will discuss a study later on which notes that resistance training ALONE preserves LBM, even when subjects follow a hypo-caloric diet. I am so going to blow your mind.
Protein Makes Me Swole, But What Other Roles Does It Play?
Well, protein itself DOES NOT make you “swole.” It’s often said that protein builds big muscles, which it does (kind of). Yes, the main role that protein plays is to serve as the building blocks of muscle. Specifically though, its main function is to REPAIR damaged muscle caused by the adaptive stress of resistance training. It’s not protein alone that makes you bigger (and stronger). It’s the adaptive response caused by the stress of training that begins the process of tissue repair. You train, muscles breakdown, you ingest protein, protein is broken down to amino acids, AA’s repair the damaged muscle, the muscles comes back bigger and stronger (assuming a proper training stimulus). While it’s borderline semantics, I just wanted to make that brief point.
- Increased TEF: TEF refers to the Thermic Effect of Feeding. Your body burns calories just to digest, assimilate, transfer, and absorb the food you eat. That being said, the TEF of protein has been said to be almost double that of carbohydrates and fats COMBINED. It’s been shown that the body will burn upwards to 25-30% of protein calories during the digestive process. For example, if you were to ingest a 100 calorie meal of protein alone, the body will burn off 25-30 of those calories. This fact alone is one main reason why many people have improved their metabolic rate just by eating more LEAN protein.
- Improved Hormone Status for Fat Loss: This is very simplified, but eating protein leads to the release of glucagon, a hormone that helps “release” free fatty acids from fat cells to be oxidized (burned).
- Improved Body Composition: This pretty much ties in with the very first paragraph, but people who eat more protein, tend to have more LBM and less fat than those who are more focused on carbohydrates in their diet.
- Increased Satiety: Protein takes longer for the body to breakdown, which helps prevent people from OVEReating during the day.
- Reduced Cardiovascular Risk: In his other book, “The Metabolic Advantage,” Dr. John Berardi discusses several studies, which have “shown that increasing the percentage of protein in the diet (from 11% to 23%) while decreasing the percentage of carbohydrate (from 63% to 48%) lowers LDL (bad) cholesterol, and triglycerides while increasing HDL (good) cholesterol concentrations.
These facts alone (along with a host of others) are why I tend to advocate that if people are going to overindulge on any of the three macronutrients, it should be protein. “When in doubt, eat protein,” a quote that I stole from a good friend, Cassandra Forsythe, a PhD student in exercise science and nutrition at the University of Connecticut. Use it as your mantra.
And while many people out there tout the dangers of high protein diets (namely those who say that high protein diets damage the kidneys), I feel that the advantages FAR outweigh the “never proven” disadvantages. Go to Pubmed or any variety of research journals and try to find ONE study that shows that diets high in protein cause damage to HEALTHY kidneys. I am more likely to make out with Natalie Portman than you are in finding such a study.
Basically, it’s not going to happen. All studies that I have seen or have been brought to my attention dealing with high protein diets and renal (kidney) failure have been done with people who have had PRE-EXISTING renal conditions in the first place. Well duh!
Protein Metabolism (I’m Keeping This Short On Purpose)
Before I discuss requirements, I think a few brief comments on metabolism are in order. Now, I am not going to go into any great detail, because to be honest, even I would get bored to tears. However, I do feel that it’s valuable to know that, “of the 20 physiologically important amino acids in the human body, only seven play a significant role as an intermediary in skeletal muscle metabolism: glutamate, alanine, glutamine, aspartate, and the branched chain amino acids (BCAA) isoleucine, leucine, and valine (1). Because it is generally accepted that BCAA oxidation (break-down) is accelerated during exercise, many experts have long advocated that trainees supplement with BCAA’s pre and post training. As evidenced by a study done by Phillips, et al, which showed that leucine oxidation increased in both males and females during prolonged endurance activity (2).
All that being said, the contribution of amino acid oxidation to the TOTAL energy expenditure is negligible during short-term exercise, regardless of intensity, and likely accounts for only 3% to 6% of the total ATP supplied during prolonged exercise in humans (3). The energy contributed by amino acids may be greater under certain conditions, such as when carbohydrate stores are low (4). In spite of this, the dominant substrates broken down for energy during EXERCISE are carbohydrates and fat.
As Forrest Gump would say, “that’s all I have to say about that.”
Requirements (What You Probably Skipped to Anyways)
Now this is where things get interesting and is where most people tend to differ with their opinions. No one really argues about the importance of protein or the roles that it plays in enhancing body composition. However, people DO argue about requirements and how much protein is really needed by any one individual. Let’s look at several different scenarios.
The ADA (American Dietetic Association) recommends that protein intake should be 0.8 grams per kilogram of body weight. Their recommendations are based solely on providing the bare minimum to stave off DEFICIENCY. So, according to these guidelines, my daily protein requirement would be ~73 grams of protein per day.
200 lbs/2.2= 91 kg
91 kg x 0.8= 73 grams of protein per day.
I never knew I was a 14 year old girl! I think it’s safe to assume that my protein requirements are going to be more than 73 grams per day to maintain my LBM and to help me recover from three to five training sessions per week. As I mentioned above, the ADA guidelines are the BARE MINUMUM required to stave off deficiency. They’re geared towards average Joe Schmo who does nothing but commute to work, sit in front of a computer all day, goes home and watches three to four hours of television, and repeats the same cycle day in and day out. Because he isn’t very active, he won’t have a negative nitrogen balance and he obviously won’t need more protein in his diet. But what about those individuals who DO lead an active lifestyle?
Substantial evidence now suggests that exercise can indeed alter protein turnover—either acutely during activity or during recovery—but the magnitude of change depends on the type, intensity, and duration of contractile activity as well as nutrition and training of the individual. The muscle response is broadly subdivided into aerobic (endurance) and resistance (weightlifting) exercise, as the adaptive response, and hence requirements, induced by chronic training differs between the two types of activity.
Aerobic Exercise: Unfortunately, from what I have found, the effect of aerobic training on protein turnover in skeletal muscle has not been determined in humans. That’s not to say that protein is not broken down during aerobic activity, it most certainly is. Case in point…take a look at the majority of endurance athletes (such as marathon runners) who have low body-fat levels, but little to no lean body mass. To say that aerobic exercise does not break down protein (muscle) would be false. However, when it comes to PROTEIN TURNOVER (breakdown/synthesis), there is no significant research that says that aerobic activity does anything definitive.
Resistance Exercise: On the contrary, there is a plethora of information in regards to resistance training and skeletal muscle turnover. Phillips and colleagues (5), confirmed that the rate of muscle fractional breakdown acutely increases three hours post-exercise and is still elevated after 24 hours, but returns to basal levels within 48 hours. In studies done by the same researchers, the effects of an eight week resistance training routine (in a fed state) showed that rates of fractional synthesis and breakdown (turnover) is muscle protein were both higher at rest FOLLOWING training. Very few studies have failed to detect significant increases in muscle protein synthesis following an acute bout of resistance exercise, and those that have, were conducted on trained individuals (suggesting that they have adapted to the exercise stimulus).
That being said, here are the protein requirements for “active” individuals based off of the research (6):
Protein requirements for “active” individuals
Because most athletes do not fall neatly into one category (aerobic or strength), a general recommendation of 1.5-2.0 grams per kg of body weight has been suggested by the NSCA (6). Personally, I have found that 1.0 grams per lb of body weight works well for the majority of people I work with.
Additionally, one’s nutritional status will effect protein requirements as well. Those who follow a ketogenic diet, generally have diets high(er) in protein (to make up for calories lost from subtracting carbohydrates). The most critical aspect of protein intake for these people is to PREVENT lean body mass loss (or is it?).
During a ketogenic diet, atleast 120-150 grams of protein are needed per day (regardless of total calorie intake) to maintain nitrogen balance and to provide glucose for the brain (7). Anymore, and you sacrifice leaving ketosis (58% of dietary protein will appear in the bloodstream as glucose).
Table of Protein Intake and Grams of Glucose Produced (7).
(assuming a 58% conversation rate)
If you remember from my “Carbohydrate Conundrum” article, I stated that the brain needs roughly 75 grams of glucose per day to function properly. I am not going to go into specifics here because you can read the article for more details, but as you can see from the table above, anything more than 150 grams of protein per day and you risk leaving ketosis.
Personally, I am not a fan of ketogenic diets (although I am fascinated with the physiology behind them), but I just wanted to point out that an individual’s nutritional status will also affect their protein requirements and that these are STILL higher than what the ADA recommends for the majority of people.
Earlier, I mentioned that the main function of protein during hypo-caloric diets is that it helps to PREVENT loss of lean body mass. Because of this, many people believe that protein requirements INCREASE while dieting and that this alone will help prevent LBM loss. While I don’t mean to “rock the boat” or make things even more confusing, I do want to touch on a study that was brought to my attention concerning Very Low Calorie Diets (VLCD) and LBM gains/loss.
VLCD diets (geared towards weight loss) typically result in loss of LBM and a decrease in Resting Metabolic Rate (RMR). To offset this, many people think that adding cardiovascular work will help prevent this cascade of events. In short…it makes things worse. The purpose of this particular study was to examine the effect that high volume RESISTANCE training in conjunction with a VLCD had on these parameters.
Two groups were made: C+D (cardio plus diet) and R+D (resistance training plus diet). Both groups consumed 800 kcal/day liquid formula diets for twelve weeks. The C+D group exercises one hour per day (4 times per week) by walking, biking, or stair-climbing. The R+D group performed resistance training three times per week at ten stations increasing from two sets of 8-15 reps to four sets of 8-15 reps.
Maximum oxygen consumption (Max VO2) increased significantly, but equally in both groups. Body weight decreased significantly more in C+D than R+D. The C+D group lost a significant amount of LBW (51 to 47 kg). No decrease in LBW was observed in R+D. In addition, R+D had an increase in RMR O2 ml/kg/min (2.6 to 3.1). The 24 hour RMR decreased in the C+D group (8).
That’s an eye opener! Essentially, what this study shows is that the addition of resistance training (not increasing protein intake) resulted in the preservation of LBM and RMR, even while drastically hypo-caloric (800 calories per day). How you like dem apples?
My Concluding Thoughts (It’s About Time)
Protein. It’s a wonderful thing. It serves MANY crucial roles in enhancing body composition and it’s darn tasty. Like with anything in life, people tend to get into the mindset that “more is better.” There are only a handful of things that people need MORE of.
1. More exercise
2. More sex
3. More cowbell
I think people tend to swing the pendulum too far to either side. On one side, you have those who feel all you need is the bare minimum to stave off deficiency (regardless of activity level), and on the other you have bodybuilders who eat upwards of 400-500 grams per day. There is no ONE perfect requirement. Hopefully I was able to shed some light on the topic and to answer some of your questions. I have a steak to go eat.
Written by Tony Gentilcore, CSCS, CPT
Discuss, comment or ask a question
If you have a comment, question or would like to discuss anything raised in this article, please do so in the following discussion thread on the Wannabebig Forums – Protein Power discussion thread.
1. Hargreaves, M., Spriet. Exercise Metabolism (2nd Ed.) Champaign, IL: Human Kinetics, 2006.
2. Phillips SM, Atkinson SA, Tarnopolsky MA, MacDougall JD.Gender differences in leucine kinetics and nitrogen balance in endurance athletes. J Appl Physiol. 1993 Nov;75(5):2134-41.
3. Tarnopolsky MA, Atkinson SA, Phillips SM, MacDougall JD. Carbohydrate loading and metabolism during exercise in men and women. J Appl Physiol. 1995 Apr;78(4):1360-8.
4. Lemon PW, Mullin JP. Effect of initial muscle glycogen levels on protein catabolism during exercise. J Appl Physiol. 1980 Apr;48(4):624-9.
5. Phillips, S.M., K.D. Tipton, A.A. Aarsland, J.C. Cortiella, S.P. Wolf, and R.R Wolfe. . Mixed muscle protein synthesis and breakdown after resistance exercise in humans. American Journal of Physiology. 1997. 273: E99-107.
6. Reimers, K., Ruud, J. Nutritional factors in health and performance. In: Essentials of Strength and Conditioning (2nd Ed.) Baechle, T.R., Earle, R.W.., ed. Champaign, IL: Human Kinetics, 2000.
7. McDonald, L. The Ketogenic Diet. 1998
8. Bryner RW, Ullrich IH, Sauers J, Donley D, Hornsby G, Kolar M,Yeater R.
Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate.J Am Coll Nutr. 1999 Apr; 18(2):115-21.