Marc S. Schneider, M.D.
Does Protein Build Muscle?
The purpose of this article is to answer one of the most commonly asked fitness questions:
Does protein build muscle?
We are going to discuss the science of protein supplementation with this ultimate guide to protein powder and building muscle.
The science behind muscle growth, exercise and protein powder is quite interesting and extensive. We will discuss:
Table of Contents
- The Different Muscle Types
- The Proteins in Muscle
- Amino Acids and Muscle Growth
- The Science Behind Weight Training and Muscle Building
- How Protein Builds Muscle
- The Best Types of Protein Powder
- How Much Protein Powder You Should Take
- Protein Timing
- Carbohydrate and Protein Powder
- Protein Absorption
- Our Recommendtions
Proteins are the building blocks of our body and are made up of various combinations of molecules called amino acids. There are over 2 million different types of proteins present in our body and each of them has a specific role to play.
Everything you eat, how you arrange your diet, and everything you do, has an effect on muscular development. The goal is to maximize athletic performance by creating a dietary muscle protein optimizer system that helps you grow, recover, and do it again.
There are three types of muscle in the body. When you eat, drink, exercise, recover, and sleep, each of these muscles is affected. Let’s review skeletal, smooth, and cardiac muscle.
Skeletal muscle is the muscle type that everyone is focused on. This is the muscle that is attached to all the bones of the body and produces movement.
There are two types of contracting skeletal muscle cells:
Slow twitch fibers that are called type I, and the fast twitch fibers called type IIa and type IIb. Type I fibers are responsible for slower, endurance type, repetitive movements. The type II fibers are responsible for speed, strength, and power. Further down we will discuss how exercise affects the different fibers.
Smooth muscle is the muscle that lines the tubes in your body: stomach, intestines, blood vessels and lymphatic vessels.
Cardiac muscle is the unique muscle of the heart. If you exercise very hard for extended periods, it grows similar to skeletal muscle. A stronger heart pumps more efficiently.
You may have wondered why athletes have a slower heart rate?
An athletes heart is stronger and does not have to pump as fast in order to push the same amount of blood.
All of these muscles contain different proteins. The proteins form the structure of the muscle, make the muscle contract and relax, and rebuild the muscle.
Muscle contraction is what produces power, and each time it occurs, proteins, enzymes, and energy substrates are used. Each contraction and relaxation involves hundreds of chemical reactions.
The Proteins in the Muscle
Now, a little more science about the 3 different types of muscle protein:
These are the sarcoplasmic proteins, the stromal proteins, and where strength comes from, the myofibrillar proteins.
Each muscle cell (myofibril) has an outside wall and it is filled with a gel called the sarcoplasm. The sarcoplasm is made up of proteins including hemoglobin and myoglobin that carry oxygen for the cell.
The stromal proteins make up the connective tissues within the muscle. We are all familiar with one kind called collagen. Collagen provides the strength, form, and structure to the muscle. Without collagen, the muscle would simply fall apart each time you flexed.
Two other stromal proteins called elastin and reticulin play important roles. While collagen is strong, it is not elastic. Elastin is what gives tissue its elasticity allowing it to snap back. Reticulin is another protein that provides structure to tissues.
So what about the protein behind muscle contraction and strength?
These are called the myofibrillar proteins. They do the work of muscle contraction and relaxation.
Amino Acids and Muscle Growth
You might be wondering:
What is the connection between protein, amino acids, and muscle growth?
It is pretty simple. Each protein is made out of a different sequence of amino acids. If you change the sequence you make a different protein. It is the amino acid sequence that makes each protein unique.
The proteins are constantly being used and remade. This is called metabolism and happens 24/7.
You may have heard that body constantly remakes itself:
This is true. All the tissues are made of protein, and all the proteins are made up of amino acids. It is a dynamic system. The proteins and amino acids are constantly joining, breaking down, and reforming. When proteins are made, this is called anabolic, and when proteins are broken down, this is called catabolic.
So that’s why amino acids and their availability are so important.
Amino acids must be available in order to make new proteins. Without an adequate amino acid supply, the tissues of the body will suffer, breakdown, and lead to disease states.
Interestingly, just feeding the body a large dose of amino acids will stimulate muscle growth. This is a process called Muscle Protein Synthesis. More on MPS in just a bit.
There are 20 different amino acids used by the body to make protein. Your body can manufacture some of these amino acids. These are called the non-essential amino acids.
Do not confuse “non-essential” with “do-not-need”. Your body needs them, but, if you don’t eat them, they can be synthesized by your cells.
The remaining amino acids that you need cannot be synthesized. The only way to get them is to eat them in the foods you consume. These 9 amino acids are called the Essential Amino Acids (EAAs). They are the reason that you must consume protein.
Three of the essential amino acids are called the Branched Chain Amino Acids (BCAAs). They make up 35% of the muscle’s proteins.
The branched chain amino acids are Leucine, Isoleucine, and Valine. Leucine is critically necessary for muscle protein synthesis.
In fact, of all the muscle protein optimizers that you can eat, leucine is the most important. When adequate amounts of leucine are present in the bloodstream, leucine acts like a switch and turns on muscle protein synthesis.
Leucine works better when it is provided to the muscle in combination with the other branched-chain aminos: Isoleucine and Valine. That’s why it is recommended that you take a BCAA supplement rather than just a leucine pill.
When the muscle is provided a large dose of branched chain amino acids prior to exercise, less damage occurs in the muscle. Scientists call this damage “exercise-induced muscle damage”. This is what causes delayed onset muscle soreness (DOMS). The reason why you can’t walk downstairs 24-48 hours after doing legs.
Athletes recover better and perform better on subsequent days if they have less exercise-induced muscle damage and DOMS. So the goal is to build you most efficiently, and have you train, recover and perform exceptionally.
So what is the better supplement for building muscle, BCAA’s or Protein?
They are both important. The branched-chain amino acids stimulate the muscle to build new proteins. This is further amplified if the other 17 amino acids + other nutritional factors found in protein powder are also provided. This is why consuming protein produces more muscle protein synthesis than only consuming BCAAs. However, protein consumption does not decrease exercise-induced muscle damage or DOMS.
So you should take both. Funny how it works isn’t it?
Exercise and Muscular Development
The brain, via the nerves, stimulates and coordinates the firing of the muscles during exercise. Exercise also stimulates the nervous system to trigger the release of different hormones. The hormones and quantity released is determined by the type of exercise performed.
Certain hormones assist in building tissues and these are anabolic. Other hormones are known to break down tissues and these are catabolic.
Aerobic exercise (long-distance running, swimming, rowing, biking etc.) is catabolic. It breaks down fat, and it breaks down muscle. It will stimulate Type I muscle fiber growth (slow twitch) for recovery.
Resistance exercise, lifting weights, is anabolic. It causes muscle breakdown and growth of Type II muscle fibers (fast twitch). Weight training produces an increase in muscle mass and myofibril cross-sectional area. Endurance training causes the body to adapt by burning more fat and decreasing muscle size.
So should you do your cardio and weight training together?
When aerobic and resistance exercise are combined, meaning performing weight training and cardio during the same training session, the hormonal and physical effect is catabolic. Yes, studies show that you convert an anabolic weight training session into a catabolic event when cardio and lifting are combined.
This is why it is recommended that cardio is performed at least 2 hours apart from weight training. Splitting your cardio and weightlifting sessions, or doing cardio on a different day, will preserve the anabolic effect of weight training.
Original Photo by Filip Mroz
Did you know that there are 2 ways that weight lifting helps muscles grow?
Any resistance based gym workout will help muscles grow. The amount of resistance and the time under tension will affect the amount of growth that occurs. There are two mechanisms at work when you perform resistance exercise.
The first is that the exercise produces damage to the muscle cells. The damage stimulates special repair cells within the muscle called satellite cells to increase in number. This increase in satellite cells is assisted by turning on specific protein factors (mTOR, IGF-1, MGF, IL-6, HGf) that increase muscle protein synthesis and produces muscle growth.
The type of muscle cell damaged during exercise determines the type of muscle cell that will grow. Heavy eccentric weight lifting preferentially damages type II muscle cells. Endurance exercise damages more type I fibers.
Weight lifting also produces a sensitivity in the muscle to the influx of amino acids. Adequate doses of amino acids provided to muscle during this time will further stimulate muscle protein synthesis.
Therefore, when the increased sensitivity caused by weight training is combined with a rapidly absorbed protein meal, the effect on muscle growth is amplified. This is why consuming whey protein following exercise is so much more effective than lifting alone.
How Protein Helps Muscle Grow
Can protein cause muscle to grow without exercise? You are going to laugh, but the science shows that it does.
Protein feeding helps muscle grow by stimulating muscle protein synthesis.The amount and type of protein that you eat will determine the amount of muscle growth that will occur.Click To Tweet
This is critical to understand.
There are two basic types of protein feeding. The first is the normal dietary intake that comes with a meal. The second type is protein consumed as a supplement. Each time you eat a protein meal, there is an increase in muscle protein synthesis (figure 1). This typically lasts for several hours. When muscle protein synthesis stops, muscle protein breakdown begins.
When you consume a protein meal three times a day, you will get a bump in muscle protein synthesis each time. The average North American consumes 10 grams of protein or less at breakfast. Two eggs have 8 grams of protein. This small amount of slow absorbing protein produces a small bump in muscle protein synthesis to start the day (figure 2).
Protein supplementation over and above the normal dietary intake, produces a much larger jump in muscle protein synthesis (figure 3). This is why protein supplementation will produce significantly more muscle growth than just “eating right”.
Protein supplementation produces more muscle protein synthesis than eating a normal protein meal.
How Protein Helps Muscle Grow
There are numerous different types of protein powder supplements that you can take:
- Whey (hydrolyzed, isolate, concentrate)
- Milk (solate, concentrate, powder)
- And then of course there are blends of all the above.
So let’s begin breaking this down:
Researchers typically evaluate the differences between whey, casein, and soy for muscle protein synthesis. Scientists and athletes want to know what is the best muscle protein optimizer. Meaning, which protein type stimulates muscle growth, strength and power the most.
Whey and soy protein powders are both considered to be fairly rapidly absorbed. Casein powder is absorbed much more slowly. Each time you take a dose of protein powder, you create an elevation in MPS. There are two factors to evaluate when looking at this elevation: 1, how high does it go, and 2, over what period of time does this elevation happen?
Researchers have specifically evaluated the amplitude MPS as measured by the amount of leucine uptake and the timing of the elevation and here is what they have found (figure 4).
- Whey Isolate is absorbed the fastest and produces high elevation
- Whey Concentrate is absorbed a little slower but produces a higher elevation
I bet you that one is a surprise!
- Casein powder produces a much lower elevation over a much longer period of time
- Soy protein powder produces more MPS than Casein but much less than Whey
Tang et al showed that without exercise, whey produces 20% more MPS than soy and 93% more MPS than casein. If taken after exercise, whey produces 32% more MPS than soy and 122% more than casein.
Besides casein being very slow to digest, it also seems to work differently. Though its MPS effect is low, it significantly decreases muscle protein catabolism far more than whey or soy. Thus, it may be beneficial if it is taken at bedtime to prevent muscle protein breakdown during the night.
We also know that there are different digestion rates for the different proteins. Whey isolate is the fastest followed by whey concentrate, soy, egg, and casein. There is also a difference in how much of the protein can be absorbed at one time. Twice as much whey can be digested per hour compared to soy and three times as much compared to milk isolate.
As we stated in the exercise section, weight training sensitizes protein synthesis to the inflow of nutrients. If you want to maximally amplify muscle growth after exercise, you need the highest quality whey protein like New Zealand Whey.
Here are several interesting facts about MPS and protein powder:
Even though consuming protein produces elevated levels of amino acids in the bloodstream for hours after it is ingested, the elevation in muscle protein synthesis happens over a shorter, very discrete time frame.
In addition, when the effects of whey hydrosylate, whey isolate, and whey concentrate were compared in a study measuring muscle growth and resistance exercise, the growth effects were similar (Perez et al). Though the MPS between the three is similar, Isolate does yield more fat loss (Roberts et al).
Whey also has numerous health effects and since the time of Hippocrates, has been demonstrated to promote health. We discussed the differences between different protein powders in greater detail in our “What Is The Best Protein” article.
Protein Amount (Protein Dose)
The amount of protein you should take to optimize muscle growth is a little controversial and confusing. So we will provide you our perspective based on numerous published studies. It is important to understand that multiple factors in these studies are varied. Physicians never jump to conclusions based on the results of one study. We consider multiple studies, assess what factors were evaluated and how it pertains to a particular subject, and then draw conclusions.
These are the facts leading to our protein dose recommendations:
In 2009, Moore et al showed that a 20 gram dose of egg protein given after exercise was better than 0, 5, and 10 grams, and just as good as 40 grams. Witard et al showed that 20 grams of whey protein given 3 hours prior to lifting increased MPS as much as 40 grams. This research group went on and evaluated whey protein immediately post-workout. They found that 20 grams increased MPS 49% and 40 grams increased MPS 56%. However, they concluded that 20 grams was sufficient.
However, this research group and lead author Kevin Tipton, went on to show landmark different results 2 years later. In this study, they measured the effect of 20 and 40 gram whey protein doses, post-workout. In addition, they evaluated the effect of what is most commonly done in the lab, one leg resistance exercise, versus the effect of combined chest press, lat pull-downs, leg curl, leg press, and leg extension. This was done to see if activating the whole body was more effective at MPS than just isolated leg exercise.
Researchers found that 40 grams of whey protein was superior to a 20 gram dose.
Tipton went on to discuss why they thought there was a difference in their latest findings. They believe that the difference was due to activating more muscle in the body, which leads to greater MPS in each muscle.
So what is the take away from this:
Taking a dose of 40 grams of whey protein produces more muscle-building protein synthesis than does 20 grams. In addition, using all your muscles in weight training will have a much greater effect than just performing isolated exercises.
Like protein dose, protein timing is a little controversial as some studies support the concept of an anabolic window, while others suggest otherwise. Aragon and Schoenfeld wrote an excellent review of the research concerning protein timing and concluded that a post-workout dose of 20-40 grams of protein clearly produces significant anabolic muscle growth. Esmark et al was the first to demonstrate a significant benefit of immediate post-workout protein supplementation versus delayed.
Morten et al wrote an excellent research review in 2015 and concluded that it is most advantageous to take protein right after a workout.
A few studies seem to contradict these recommendations though they’re considered by many not to be good research models of protein timing.
Original Photo by Sabri Tuzcu
Hoffman et al saw no difference in body composition (body fat and lean mass measurement) comparing protein taken in the morning and evening, versus protein taken before and after weight training. The researchers did not measure muscle protein synthesis, strength, power or perform muscle biopsies. Erskine et al showed no benefit to protein at all, but the researchers only evaluated athletes doing arm curls. As we discussed earlier, isolated resistance exercise produces less muscle growth.
So what is the take away here?
We know that the duration of sensitivity to elevated amino acids caused by resistance exercise lasts 24-48 hours. Science has shown that post-exercise supplementation is superior to pre-exercise. No one has determined whether there is a muscle growth difference taking a protein supplement 1 hour after workout vs 2 hours, 3 hours etc.
Most sports nutrition scientists agree however that protein supplementation should be given post-exercise.
Should you take protein powder more than once-a-day?
We know that each time you drink at least 20 grams of a whey protein powder supplement, muscle protein synthesis is activated. Areta et al in 2013 showed that dosing 20 grams of whey every 4 hours after exercise was very effective.
NHL strength coach Justin Roesthlingshoefer has his players take whey protein many times a day. “It really depends on each guy, the goals, and how they maintain weight” (personal communication).
Carbohydrate and Protein
Carbohydrates are a key energy source as discussed in our Guide to Macronutrients, and the glucose levels they produce support optimized athletic performance. The body stores glucose in the form of glycogen. Glycogen storage is very limited and once it is depleted, glucose must be supplied to the body in the form a fast absorbing sugar. Without adequate glucose, the brain and muscles will suffer.
Intense exercise can quickly drain the glycogen reserves.
Without a carbohydrate source, the body burns fat and turns it into sugars for fuel. This is a slow process, and though it may be the rage with ketogenic diets, it is not ideal for athletic training or performance.
The replenishment of depleted glycogen stores by consuming carbohydrate is essential for a training athlete. Nutritional timing studies for glycogen replenishment also suggest that carbs should be taken post-workout.
What does research show about carbohydrate and muscle protein synthesis?
Carbohydrate intake will stimulate elevated insulin levels, and this will decrease muscle protein breakdown. Robinson et al have shown that elevated insulin levels combined with elevated amino acid levels increases muscle protein synthesis. Others (1, 2) have shown similar results.
However, it appears that the effect of elevated amino acid levels from whey protein consumption is more than enough to stimulate MPS. Numerous authors including Phillips and Staples have shown no benefit in MPS comparing protein + carbohydrate versus protein alone.
So should you take carbo’s with your protein?
We think it really depends on your goals and your exercise program. If you work out moderately, you may not drain your glycogen stores and you may not need carbohydrate supplementation. If your goal is solely to increase muscle size, minimize body fat, and you exercise intensely, you should consume some carbohydrate with your protein.
Athletes who exercise intensely 5-6 times a week should absolutely look to restore their glycogen stores daily, and this will typically include taking a 2:1 ratio of carbs to protein following their exercise.
Protein is digested and absorbed at different rates and at different times. The goal is to absorb the protein powder as quickly as possible.
Whey isolate is digested the fastest at a rate of about 10 grams per hour. Soy isolate is absorbed at about 4 grams per hour. You can see a protein absorption chart in our Guide to Protein Absorption.
So you must be asking…
How can you absorb 40 grams of protein very quickly if whey isolate can only be digested at 10 grams an hour? Great question. The answer is digestive enzymes.
Digestive enzymes will increase the protein absorption rate by 2.2 – 3.0 times. Numerous protein powder manufacturers only put digestive enzymes in their whey concentrate products. They do not put it in their whey isolate.
Whey concentrate has lactose, which can be difficult to digest for some. Digestive enzymes aid in lactose digestion. Whey isolate has no lactose so manufacturers seeking to cut costs, leave the digestive enzymes out. Unfortunately, this reduces how much of their whey isolate can be absorbed. Amazingly, products like Dymatize Iso100 and Isopure have no digestive enzymes.
Whey protein powder is by far the best post-workout muscle protein optimizer. It produces more muscle growth than any other protein. This results in increased speed, strength, size and power.
New Zealand Whey Protein combines the purest, 100% grass fed whey isolate and whey concentrate from New Zealand. The blend of the two proteins produces extremely high muscle protein synthesis over two time frames to sustain the muscle growth effect.
In addition, the native whey concentrate that we use has health promoting proteins that are lacking in pure whey isolate. The 94% protein whey isolate in NZWP has the highest concentration of protein in an isolate and promotes more fat loss.
We believe the ideal dose post-workout protein supplementation is 40 grams. You should also take 25-40 grams of whey protein several times a day to maximize muscle building and to shut down muscle breakdown. Take a scoop when you first get up in the morning, after your workout, and then before bed.
Remember, fortune favors the bold, fortune favors the strong.