Protein intake is specific to each individual, their unique metabolic needs and training demands.
That’s why it’s often gauged against metrics that are specific for that person, like their weight or the amount of calories they eat per day.
In order to gain muscle, the body has to make sure it is taking in more nitrogen than it is using for structural and functional maintenance of bodily processes.
Amino acids, the building blocks of protein, are some of the most abundant sources of nitrogen. Through providing an essential source of this element, amino acids provide the basis for muscle protein synthesis, helping to maintain and grow body protein content, and therefore muscle mass.
The body also needs to use proteins for other essential maintenance functions that aren’t just structural, such as detoxification, making hormones and neurotransmitters (brain chemicals), and acting as a reserve energy source.
So once it has enough to fulfill these basic maintenance needs, excess protein can be used to grow muscle mass.
Even though dietary protein can act as the fuel and metabolic signal to turn on muscle protein synthesis by itself, resistance training is also necessary to optimally stimulate new muscle growth.
Ok so we know why we need protein, by how much do we need as individuals?
So the scientific consensus (which has been examined ad nauseum) is that ~0.3g/kg/meal of high quality protein is enough to maximally stimulate muscle protein synthesis after a single meal, and should be repeated every 3hrs throughout the day (1).
So for an average person of 70kg that would be (0.3g x 70kg = 21g protein per meal).
This equates to 1.2g protein / kg per day (when considering 3x meals and snacks).
The general scientific consensus is that 1.2g/kg is the lower level for catering for muscle gain. Some studies suggest consuming levels of up to 2g of protein per kg of body weight (2).
It is also important to consider that a deficit in overall calories (fat, carbohydrate and protein), so taking in less energy than one is expending on a day to day basis will lead to gradual muscle loss even if protein intake is meeting or exceeding the above recommendations (0.3g/kg per meal).
What about Protein Quality?
Well, not all amino acids are built the same, and they all contribute to different degrees when it comes to stimulating muscle growth, based on their availability in the diet, and the body's ability to make them itself.
Some amino acids are considered essential because they can’t be made by the body, and must be obtained from the diet.
Non-essential amino acids can be made by the body, and don’t need to be obtained from the diet.
Others are conditionally essential, meaning they can be made in a limited capacity from non-essential amino acids, usually under special circumstances like stress or illness.
This is where food choices are important when it comes to getting enough of all the amino acids, in particular the essential ones that contribute to muscle growth.
A source of protein that contains all the essential amino acids is often referred to as a ‘complete’ protein.
Complete protein sources include:
- Dairy products
Plant based foods, such as grains, legumes, nuts, seeds, fruit and veg when considered individually are not complete protein sources as they often lack one or more of the essential amino acids.
However, when combined they can make a complete protein source, such as eating rice with beans.
So if eating a plant based diet, ensure a diverse consumption of many different grains, nuts, seeds and legumes to meet high quality protein demands.
When it comes to building muscle, there are 3 essential amino acids to pay attention to in particular, which are also called Branched Chain Amino Acids (BCAA’s), called leucine, isoleucine and valine, and they account for almost 50% of muscle protein essential amino acids (3).
Leucine in particular acts as both a fuel source for muscle protein synthesis as well as a driver of the actual process itself (4).
A few foods high in BCAA’s are:
- Brown Rice
How do you actually calculate protein intake?
So when working in grams, to achieve muscle gain a person needs to eat a minimum of 1.2g/kg body weight.
So depending on a person's total protein in g based on their body weight, they can look to split the total requirements into 4 roughly equal servings throughout the day.
This is very easy to measure with supplements like protein shakes, as it specifies the amount of protein in g per serving. Its usually somewhere between 20-30g per serving.
Prepared foods it’s the same deal - very easy to see the amount of protein in g per serving according to the label.
Some of our providers on The Meal Prep Market make it super easy to meet daily protein requirements for muscle gain, as they list the nutritional content of protein for each meal in g.
Be sure to check out these particular providers in the App 👉
- Out of the Box
- Fit Food Tasty
So someone can easily tell if they are meeting their protein intake each meal if it's close to 20-30g.
With foods prepared at home, one has to do a bit of work to calculate how much they are consuming.
It’s still easy though, especially if each meal is composed of a single item that is majority protein:
- A single average chicken breast (100g) contains ~ 30g protein
- A single average steak (100g) contains ~ 25g protein
- A single average salmon filet contains ~ 25g protein
- A serving (100g) of lentils contains ~ 10g protein
It’s simply a case of eating 3-5 servings of the above items (non exhaustive list)
Measuring protein as a percentage of calories
Another way some people like to measure protein intake is to measure it as a percentage of total calories consumed.
So if someone calculates their Total Daily Energy Expenditure (~ 2,000 Kcal), which is the amount of energy needed for basic bodily functions plus any exercise or physical activity on top of that each day, then they know they need to eat in excess of that each day.
Usually it’s an excess of around 300 calories (Kcal), but it really depends on the individual and their goals.
But, in order to gain muscle optimally its handy to know what percentage that protein makes up of those total calories as well. This is because if all the calories were coming from carbohydrate and fat, then the weight gain would be less muscle and more fat potentially.
So let’s say a person needs to eat about 2,300 Kcal / day to gain muscle based on the above total daily expenditure of 2000 Kcal / day.
Usually diets of around 20-35% protein of total calories support muscle gain (5). So in this case that’s 460 Kcal or protein, equating to 115g protein / day.
Protein is measured as 4 calories per gram, so when you can interconvert between calories and grams easily.
When you see the macros listed on our app for example, including the protein, carbohydrate and fat content you can easily work out how many calories each one makes up of your total calories.
So for example, let’s consider the below recipe:
So 472 calories in total….
Carbs are also 4 calories per gram so 49g x 4 = 196 calories
Protein is 4 calories per gram so 42g x 4 = 168 calories
Fat is 9 calories per gram so 12g x 9 = 108 calories
To get percentages of each of total calories:
Carbs is 196/472 x 100 = 42%
Protein is 168/472 x 100 = 35%
Fat is 108/472 x 100 = 23%
It’s handy to know both how many total grams of protein you eat in a day to ensure optimal muscle growth (especially if you are training hard), as well as the percentage of overall energy your protein intake is. So that you can make sure your protein intake is in good proportion to other macros to gain lean mass as opposed to just mass.