Protein Synthesis: How To Grow Muscle

Allow me to get just a little nerdy with you for a minute or two. I know what I have to share below is technical enough that it will be boring to some of you and fascinating to others. Regardless of which group you fall into, having a solid understanding of the basic physiological interactions that happen when you eat and work out is important because it gives you the ability to better discern what programs and authors are giving you the straight scoop and which ones are full of bologna.

Even more importantly, knowing “why” provides many folks the extra motivation and discipline to do things in a way that will most likely garner the results they seek. Let’s start with how muscles grow…

How Muscles Grow

Muscles grow via a complex process that involves numerous cellular functions and factors which come from leveraging resistance in one form or another (weight training, etc.). Basically, to build muscle, one must break down muscle fibers (catabolism) through the process of weight training, and then build up those fibers through the synthesis of muscle protein (anabolism). Protein synthesis refers to the creation of protein by the body’s cells, and this protein is literally the building block of muscle development and other body functions.


Proteins are the polymer chains of amino acids necessary for most processes within the human body. Next to water, protein is the most abundant molecule found in the human body, and most tissues in the body require protein as a basic building block. Protein also serves as a fuel source.

There are three different types of amino acids:

  • Essential
  • Non-essential
  • Conditional

Essential amino acids must be taken in via food, as the body cannot create them. Essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Non-essential amino acids are created in the body by essential amino acids or through protein breakdown. Non-essential amino acids are alanine, asparagine, aspartic acid, and glutamic acid

Conditional amino acids are not essential, except for people who are injured, stressed, or ill. Conditional amino acids are arginine, cysteine, glutamine, glycine, proline, serine, and tyrosine.

While the conditional aminos might not be required, they still obviously have benefits – like glutamine and tyrosine, for example. But then again, we can certainly say that someone engaged in intense bodybuilding training is definitely “stressed”!

Amino acids are obtained through the consumption of meat, milk, eggs, and fish, as well as plant sources. Animal proteins are complete, while plant-based proteins are incomplete. Complete proteins contain sufficient amounts of all essential amino acids, while incomplete proteins either have insufficient amounts of all essential amino acids or are missing one or more of the essential amino acids.

When Protein Synthesis Occurs (How Exercise Affects Protein Synthesis)

Protein synthesis in the skeletal muscles (as opposed to the heart muscle, which uses other processes) builds muscle after extensive resistance is performed (i.e. a heavy-lifting workout). Post-workout, protein synthesis is acutely stimulated, which means that for three to four hours after a workout, protein synthesis begins to increase by about 50%. At about 24 hours after a workout, the increase peaks at around 109%, then slowly returns to baseline levels between 36 and 48 hours post-workout. It is during the climbing phase that the consumption of proteins is essential to aid in protein synthesis; otherwise, the muscles will actually break down in order to provide protein for your body’s cells, which will not only halt muscle growth but reverse it (called muscle wasting or sarcopenia).

The best workouts to build muscle (hypertrophy) involve progressive overload, which can be achieved through increased:

  • Volume
  • Resistance
  • Repetitions
  • Sets
  • Time under tension
  • Exercises
  • Frequency
  • Intensity
  • and/or Efficiency

Decreasing rest time between sets or workouts can also cause hypertrophy. It has been shown that the performance of multiple sets of weight training exercises is 40% more likely to cause hypertrophy by way of increased protein synthesis compared to performing single set weight training exercises.

How Diet Affects Protein Synthesis

In order to build muscle, one must eat at a caloric excess; in other words, take in more calories per day than what is needed to maintain and run the body’s processes. To determine maintenance calories, one must figure out BMR and activity levels. Basal Metabolic Rate (BMR) refers to the minimum calories required to maintain the body’s processes.

Use the formula to determine BMR for men:
BMR = (13.7516 x weight + 5.0033 x height – 6.755 x age + 66.473) kcal/day

Use the formula to determine BMR for women:
BMR = (9.5634 x weight + 1.8496 x height – 4.6756 x age + 655.0955) kcal/day

*weight is in kilograms, height is in centimeters, and age is in years

How to Determine Total Daily Energy Expenditure:

Once a person knows his or her BMR, he or she can determine maintenance calories, also called Total Daily Energy Expenditure (TDEE). Multiply the BMR by a metric that indicates activity level to determine TDEE. Activity levels are sedentary, lightly active, moderately active, very active, and extremely active:

  • Sedentary = desk job with little to no exercise
  • Lightly active = light sports or exercise one to three days per week
  • Moderately active = moderate sports or exercise three to five days per week
  • Very active = hard sports or exercise six or seven days per week
  • Extremely active = hard daily sports or exercise plus a physically-demanding job

Sedentary: multiply BMR x 1.2

Lightly active: multiply BMR x 1.375

Moderately active: multiply BMR x 1.55

Very Active: multiply BMR x 1.725

Extremely active: multiply BMR x 1.9

The goal is to increase calories over maintenance to the point where muscle mass increases via protein synthesis, but not so much that the body increases fat stores. So if your TDEE is 3,000 calories, you’re going to need to intake MORE than that in order to actually put on mass. How much more depends on your goals, metabolism, the propensity to store excess calories as fat, etc.

Ideal Amount and Timing of Protein Intake

The amount and timing of dietary protein intake is important when it comes to building muscle. Opinion differs when it comes to the required amounts of protein. The National Strength and Conditioning Association recommends 1.5 to 2 grams of protein per kilogram of body weight for building muscle.

Personally, I think that’s a bit low. As an example, for a guy weighing in at 185lbs (83.9kg – just divide lbs by 2.2 to get kg) – that’s only a window of between 125-168g of protein per day. My guideline is 1.5-2g of protein per pound of lean body mass. So that same guy weighing 185 at 12% bodyfat has a lean mass of 163 lbs. So he should be consuming between 245-325g per day if he’s trying to add lean mass to his frame.

Like I said, opinions differ – at the end of the day you’ll have to judge for yourself based on your progress, but keep in mind that a lot of the literature refers to “athletes”, which in my mind differs a bit from someone training with the express purpose of putting on a lot of lean mass, like you and me.

As for timing of the protein intake, it’s essential that a person consume sufficient protein during the protein synthesis window following a workout in order for optimal muscle building. The first few hours post-workout is an ideal time to consume the majority of the day’s food.

Start out with a post-workout supplement like Nitrobol followed 15 minutes later with a supplement that’s a combo of 20-40g of protein and 40-60g of clean high-glycemic carbs to maximize your insulin response and nutrient uptake…gotta get that protein INTO the cells! One to two hours later follow that up with a whole food meal of 30-40g of protein (meat) and 40-50g of slow-burning carbs like quinoa or brown rice.

Dietary Omega-3 Fatty Acids and Protein Synthesis

Several studies have shown that dietary omega-3 fatty acids increase muscle protein synthesis. Omega-3s have an anabolic effect in both healthy young adults as well as in older adults. The study mentioned had participants taking 4g of omega-3 supplements per day, but the minimum recommended dose is:

  • Men 19 years and older = 1.6 grams/day
  • Women 19 years and older = 1.1 grams/day

Good dietary sources of omega-3 fatty acids are salmon, ground flaxseed, and walnuts. Added benefits of omega-3 supplementation include increased cardiovascular health, accelerated fat loss, reduced inflammation, and protection from some neurological disorders such as depression and Alzheimer’s disease.

There you have it. Hopefully, you have a better understanding of the basic physiology behind building muscle, protein synthesis and why diet is so significant to achieving any strength and physique goal.

I recommend you do the math above to find out your target caloric intake and rough protein requirements and see if you’re anywhere close to your current diet. If you’re not, now you have a good place to start looking when wondering why you’re not hitting your goals.

Chances are pretty good that unless you’re planning your meals for an entire week in advance and preparing everything ahead of time, you’re not getting enough protein and you’re getting too many empty carbs…at least I know that’s what happens to me when I’m not on top of my game.

Let me know what you think about the article, and as always…

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