All about Macros – Protein

This article is all about the science and research behind protein as a macronutrient. Click here for a guide to protein supplements or click here for a guide to building muscle.

If You Want to Build Muscle, Eat Protein

If you want to build your body in any meaningful way, you need the right building materials. Proteins are the ‘bricks’ that make up all of the soft tissues in our bodies, including muscle. This is why protein has such an intertwined relationship with fitness, especially anything bodybuilding related.

Having a protein-rich diet enables our bodies to better recover from the stressors we place on them during exercise and improve performance by making bigger, stronger tissues. At a glance, this seems simple – eat a lot of protein, get strong – but there are some nuances. Protein, in and of itself does not make a healthy diet but it can certainly contribute to a healthy diet when the right considerations are made.

What are the right considerations to be made about protein consumption?

The right considerations are best thought of as the most common questions people have about protein and their diet:

How does protein turn into muscle?

How much protein do I need to eat?

Is there a specific time I should eat more protein?

What are the best sources of protein?

We are going to break down the research on protein to effectively answer each of these questions and provide you with takeaways that you can start using immediately.

How Does Protein Become Muscle?

When we eat protein our stomach acid unravels the larger protein molecule into simpler shapes that are more easily digested into its smaller building blocks; Amino Acids. These Amino Acids are then repurposed by the cells of the body to heal damaged tissue, send cellular signals, and yes, make bigger muscles.

The process of converting amino acids into muscle tissue proteins is called Muscle Protein Synthesis or MPS. MPS is always occurring in the body to some degree but so is the opposite process Muscle Protein Breakdown or MPB. When these two processes are balanced there is no change in muscle mass. In order for muscle growth to occur Muscle Protein Synthesis must be greater than Muscle Protein Breakdown. Consuming protein, and enough of it, actually boosts MPS and decreases MPB, leading to hypertrophy (muscle growth).

The obvious strategy from here would be to eat such a large amount of protein that we are always boosting MPS and inhibiting MPB. This is where people get the idea that you should eat 1.5-2.0 grams of protein per pound of body weight per day! Unfortunately, if you’re not on muscle building drugs, this is pointless. Eating that much protein won’t actually stimulate better muscle growth and it’ll probably leave you feeling like crap, which can affect your workouts and lead to a loss of muscle mass.

This might feel confusing and you might be asking yourself “How can I eat enough protein without eating too much? What is Enough and Too Much?” Luckily, the world of scientific research has done a lot of work with protein and can provide clear answers to these questions. These are answers we can use when designing our smart dieting plans so that we maximize muscle protein synthesis and minimize muscle protein breakdown, thereby optimizing the balance between the two.

How much protein should I eat?

There’s something to be said for bodybuilders. For years they swore by high protein diets and now there are multitudes of studies that show that high protein intake supports greater hypertrophy than controls, proving what they preached for decades. Most natural bodybuilders recommend eating 1 gram per pound of bodyweight (2.2 g per kg), or somewhere close to that, and this recommendation is well supported research.

Does that mean you have to eat that much protein to build a lean physique?

Not quite, research shows that 1g per pound may actually be a slight overestimation. In a study on wide range of athletes, researchers found that the average protein intake was 0.68 g/lb (1.5g per kg). A more recent study on bodybuilders found that MPS was maximized between 0.77 and 1.0 g/lb (1.7 and 2.2 g/kg). Together these data suggest that it is certainly feasible to build an athletic physique on as little as 0.68g/lb and that MPS may be maximized on as little 0.77g/lb for some people.

The bottom line on how much protein you need to eat everyday comes down to your priorities. If you want to make sure you are maximizing MPS beyond a shadow of a doubt, then you need to eat 1.0g per pound. That simple recommendation is going to be the best guideline to follow for this case. However, if your goal is to simply improve your overall physique and you don’t care as much about building every ounce of muscle possible then you can go as low as 0.70g per pound. It all depends on your priorities and tastes.

Is there a specific time I should eat more protein?

Lukas Blazek

The next consideration with protein is when to eat it. Protein timing is a hotly debated topic, with sides claiming it’s critical to eat your protein at specific times of day and others claiming total protein intake over the course of the day is all that matters.

The protein timing argument is that we can only boost MPS for small windows of time and that we can only digest small amounts of protein, 20-35g, at a time. The idea here is that we eat 20g of protein with breakfast, and by lunch we can stimulate MPS again by eating another 35g, then 20g more with a few snacks, and 40g at dinner. Each of these times were are “boosting” our muscle building processes without wasting a single amino acid. This is why bodybuilders have the reputation of eating 5-8 meals a day, to repeatedly spike MPS.

There’s also a subsection of the protein argument called the Anabolic Window. The belief is that protein infested immediately after a workout is more likely to be converted directly into muscle mass. Stu Phillips’ research supports the notion that it is beneficial for hypertrophy to ingest 20-25g of high quality protein around exercise to maximally stimulate MPS. However, you can have it before or after your workout, there isn’t really a difference. In general, resistance training makes our muscles much more sensitive to MPS, but this effect doesn’t last an hour, it lasts closer to two days.

The opposite approach would be to eat all of your protein in a small amount of time. This is often the approach of intermittent fasting in which one does not eat for a significant portion of the day and then eats all of their calories in a small window of time. For example, fasting for 16 hours and eating for 8. One study found that subjects that ate all of their calories and protein within an 8 hour window retained strength, and muscle mass just as well as those who had unrestricted eating times during an eight week diet.

When it comes to preserving lean mass and losing fat when you consume your protein is nowhere near as important as how much you’re consuming. It all comes down to what works best for your lifestyle. If you’re usually very busy and can only eat two larger meals in a day then take the intermittent fasting approach. If you have the ability to eat multiple smaller meals, and you enjoy it, then take that approach.

What are the best sources of protein?

Protein is in almost any type of food you consume, but there are some foods that we think of as ‘protein sources’ that we rely on more heavily when eating a high protein diet. Some examples include beef, chicken, soy, peas, brown rice, chickpeas, dairy. The point is that here are many sources of protein, but not all protein sources are digested equally as well.

Protein quality is measured by its protein digestibility-corrected amino acid score (PDCAAS). Some of the highest scoring protein sources are milk, soy, and eggs, all of which have a perfect PDCAA score. Animal protein tends to have higher PDCAA scores and has repeatedly been shown to be more effective at promoting MPS than plant proteins – Dairy Vs. Plant, Anabolic Response in Animal Vs. Plant Proteins.

This does not mean vegetarians are doomed to have less muscle mass ham their meat eating counterparts. Vegetarians may simply require more of their protein to achieve similar levels of muscle protein synthesis to meat eaters because of plant proteins lower digestibility scores. This is thought to be a result of the amino acid composition of plant proteins lacking certain amino acids directly reported to stimulate MPS – such as leucine.

The takeaway with protein sources is that animal sources, especially milk proteins, may be more easily digested and converted into muscle mass. Vegetarians may require more protein to account for the lower digestibility of plant protein sources. The healthiest approach is to have a variety of protein sources, both plant and animal, available in your diet in sufficient amounts.


Proteins are digested into individual amino acids that the body then reorganizes into new proteins.

There are two opposing processes always occurring in the body at different rates: Muscle Protein Breakdown and Muscle Protein Synthesis.

For meaningful muscle growth to occur, muscle protein synthesis rates must exceed muscle protein breakdown rates.

Consuming protein boosts muscle protein synthesis, and slows down muscle protein breakdown.

If you want to build as much muscle as possible, aim to eat 1 gram of protein per pound of bodyweight per day (Less if you’re very overweight).

1 gram of protein per pound of bodyweight is a good goal, but you can go as low as 0.70 grams per pound and still build an athletic physique.

When you eat your protein does matter, but not as much as how much you are eating.

In general, animal proteins digest more efficiently than plant proteins, and are better at boosting muscle protein synthesis.

Vegetarians and Vegans may require a slightly higher protein intake to get similar levels of muscle protein synthesis as non-vegetarians.