How much protein do you really need for optimal muscle growth? An update based on the latest science.

Key points:

1. For optimal muscle growth you need to eat quite a lot of protein. Scientific recommendations run from 1.6 to 2.2 grams of protein per kilogram of body weight per day. However, the vast majority of studies show no further benefits of a protein intake above 1.6 g/kg. Although it is fine to aim for 2 g/kg/day for safety and convenience. However, do not eat too much protein (so more than ~2.2 g/kg/d), because that will unnecessarily affect your carbohydrate intake. And carbohydrates are also very important for muscle building.

2. With an energy deficit, in the cut, you eat a little more: around 1.8 g/kg/d. As your fat percentage decreases, you may need even more protein to protect your muscle mass (up to 2.7 g/kg/d). But don’t eat more protein than necessary during the cut, since you already have to cut back enough on carbohydrates due to the calorie restriction.

3. If you do body recomposition (building muscle and losing fat at the same time), you can keep the same values as in the bulk: 1.6-2.2 g/kg/d.

PROTEINS AND THEIR ROLE

Protein is a macronutrient that provides amino acids and calories. It plays a supporting role as an energy supplier. Although proteins contain the same number of calories per gram as carbohydrates, the body is not efficient at converting them into glucose. It only works if no other energy source is available.

Proteins are much more important as a supplier of amino acids. Proteins contain chains of amino acids. Your body breaks these chains down into individual amino acids, which in turn serve as building blocks for the protein in your body cells – compare it to a child who breaks down a LEGO building and builds something else with the same bricks. About 70% of the amino acids from the proteins in your food end up in your cells. These cells together form tissues, such as muscle tissue, but also organs such as your heart and lungs.

In addition to a (muscle) building function, proteins also play a role in numerous hormonal and other processes. They also stimulate and facilitate muscle protein synthesis, which is of great importance for strength athletes whose main goal is muscle growth. Especially bodybuilders. More on that in a moment.

SOURCES OF PROTEIN

There are animal and vegetable sources of protein.

The main animal sources are meat/poultry and fish, dairy products (milk, cheese) and eggs. The best-known animal protein is perhaps casein, which is found in milk. Whey protein is especially popular among bodybuilders , whether or not in the form of powders or snacks (such as protein bars) or other nutritional supplements.

The main vegetable sources of protein are bread, grains such as rice and pasta, legumes and nuts.

Animal protein, unlike most vegetable protein, contains all essential amino acids, i.e. amino acids that the body cannot make itself and must therefore be obtained from food. Vegans would therefore do well to eat a varied diet and to get their proteins from as many different sources as possible, by including sufficient grains and legumes in their diet.

PROTEIN REQUIREMENT FOR NON-ATHLETES

The average adult needs about 0.8-1 gram of protein per kilogram of body weight per day. So 64 to 80 g for a person weighing 80 kg, according to the recommendations of the Health Council, dating from 2001 ^[ i ] .

In summary:
Protein requirement for non-athletes: 0.8-1 g/kg/d.

PROTEIN REQUIREMENT FOR ENDURANCE ATHLETES

Proteins have a double function for (endurance) athletes : they ensure the recovery and construction of new muscle tissue and prevent the body from using the proteins from the muscle cells as fuel. Endurance athletes, just like vegetarians, need 1-1.6 g/kg/d, depending on how intensively they exercise ^[ ii ] .

In summary:
Protein requirement for endurance athletes: 1-1.6 g/kg/d.

PROTEIN NEEDS STRENGTH ATHLETES IN GENERAL

For strength athletes in the broad sense of the word (bodybuilders, powerlifters and weightlifters) a recommendation of 1.4-2 g/kg/d applies. The exact requirement depends on factors such as training target, training volume and intensity, age, body composition and total energy intake ^[ iii ] .

In summary:
Protein requirement for strength athletes in general: 1.4-2 g/kg/d.

BODYBUILDERS’ PROTEIN NEEDS

The main goal of bodybuilders is muscle growth. For them, it is therefore not so much about sporting performance per se, although this is of course necessary to stimulate muscle growth.

In terms of nutrition, muscle growth requires proteins (amino acids), water and energy (glycogen and triglycerides). You get that energy from your daily food intake (if you use a calorie surplus) or possibly from your existing fat reserves, if they are large enough.

Proteins therefore have two functions for bodybuilders: on the one hand, repairing muscle damage as a result of sporting performance (ie strength training), on the other hand building new muscle mass. In both cases, proteins from food turn into muscle proteins by rebuilding amino acids. The production of muscle protein from amino acids is also called muscle protein synthesis. Muscle growth requires a positive balance of muscle protein synthesis. That is, the build-up of muscle protein must be greater than its breakdown.

SCIENTIFIC RECOMMENDATION

Due to the dual function of proteins, bodybuilders need more protein than non-athletes and even more than endurance athletes and other strength athletes. But how much exactly?

A meta-analysis of 49 studies with a total of almost 2000 participants resulted in a recommendation of 1.6 grams of protein per kilogram of body weight per day ^[ xxv ] .

Eating less protein means less muscle growth. To illustrate: according to a smaller meta-study you will build 0.7 kg more muscle growth over 12 weeks if you take 50 g extra protein on training days with a regular intake of 1.2 g/kg/d (which is therefore below average) ^[ iv ] . A significant difference.

Eating more protein (than 1.6 g/kd/d) did not result in extra muscle growth in the vast majority of cases, which a recent study has once again confirmed.

NOTES

Given the size of the meta-analysis, 1.6 g/kg/day seems a sound recommendation. However, there are some remarks to this:

The majority of the analyzed studies were conducted on inexperienced, young strength athletes. The results may be different for older strength athletes. For example, it has been shown that older men (fifty-plus) need more protein to maintain muscle mass ^[ v ]^[ vi ] . They may therefore also need more protein to achieve optimal muscle growth.
However, it does not seem that you need more protein the more advanced you are as a strength athlete. On the contrary: advanced users probably need less protein than beginners ^[ vii ]^[ viii ]^[ ix ]^[ x ] . As you train longer, your body becomes more efficient at limiting muscle breakdown as a result of training. As a result, you need less protein on balance to facilitate muscle protein synthesis. Nevertheless, it is best to play on the safe side and continue to use 1.6 g/kg/d as the minimum protein intake, in our opinion.
The subjects in the studies used a calorie surplus. So they ate something above maintenance to make sure that muscle growth could take place (bulking). However, you may need more protein if you are in a calorie deficit (cutting), as another meta-analysis suggests ^[ xi ] . A recommendation of 1.6–2.7 g/kg/d ^[ xxxiii ] applies to advanced strength athletes who aim to lose weight and therefore train for a long time with a calorie deficit. And: the lower your fat percentage, the higher the protein requirement. As a guideline for during the cut, we use 1.8 g/kg/d (with a higher intake at fat percentages below 10%), which we explain in more detail in this article.
Animal protein sources are better at stimulating muscle protein synthesis than vegetable ones. This is due to their higher biological value and their higher digestibility. To get all essential amino acids in sufficient quantities as a vegan, you have to eat 20-30% more protein than normal, so at least 2 g/kg/d ^[ xxviii ] .
Protein requirement expressed in grams per kilogram of lean body mass may be more accurate than grams per kilogram of body weight. But to calculate lean body mass, you have to know your fat percentage quite accurately and that is difficult to measure. Since bodybuilders usually do not have extremely high fat mass, grams per kilogram of body weight should nevertheless suffice.

PRACTICAL RECOMMENDATIONS

We therefore use 1.6 to 2.2 g/kg/d as a general recommendation for protein intake during bulk. This means that 1.6 is already sufficient in most cases, but that depending on training status, age and diet, you may need a little more to optimally facilitate muscle growth.

During the cut, a recommendation of 1.8 to 2 g/kg/d applies. It should be noted that with a limited energy deficit 1.8 g/kg/d is usually sufficient and with an extremely low fat percentage, intakes of up to 2.5 g/kg/d are necessary. In the latter case, you will probably need to implement strategies such as refeeds and diet breaks in order to maintain your training performance somewhat.

In summary:
Bodybuilders’ protein requirements: 1.6-2.2 g/kg/d (bulk) and 1.8-2.7 g/kg/d (cut).

PROTEIN AND HEALTH

In any case, as a bodybuilder you eat significantly more protein than a mere mortal. Is that actually safe? After all, it is sometimes claimed that (excessively) eating a lot of protein is bad for the kidneys and bones. But that has been amply disproved by science. In healthy individuals, a high protein intake poses no risk to kidney function ^[ xiii ] , nor to bone health ^[ xiv ] .

EATING MORE PROTEIN THAN NECESSARY

Protein facilitates muscle growth (or muscle maintenance), so why not take in extra? So (much) more than the recommended 1.6-2 g/kg/d (bulk and cut)? It can’t hurt your health, after all?

Answer: because that does not result in extra muscle growth, but it does come at the expense of the intake of the other macronutrients that are also important – carbohydrates and fats.

Now you will usually get a sufficient amount of fat (~0.7 g/kg/d is more or less the minimum), but if you eat an excessive amount of protein, for example 3 g/kg/d, then that will be at the expense of your carbohydrate intake. And that while carbohydrates are important for muscle growth in several ways, essentially being just as important as proteins ^[ xxx ] . For example, carbohydrates are the primary energy source for your workout, via the glycogen stores in your muscles ^[ xvi ] .

In this way, eating too much protein can even have a negative effect on your body composition (not for your health, as we saw). This is especially the case in the cut, when you already have to cut back considerably on carbohydrates. Coach and author Mike Israetel calls this ‘The Caloric Constraint Hypothesis’:

The Caloric Constraint Hypothesis tells us that there IS something like “too much of a good thing,” because the addition of too much of that good thing (protein, in this example) comes at the expense of other “good things” (carbs, dude). ^[ xxxii ]

This is reflected in the figure below: the most optimal protein intake for muscle growth is between 1.6 and 2.2 g/kg/d. If you eat even more, it can negatively affect your body composition (mainly indirectly, due to reduced exercise performance). If you eat less, it will come at the expense of muscle growth.

The optimal protein intake for muscle growth is between C and D. Chart taken from Renaissance Periodization .

PROTEIN INTAKE IN BODY RECOMPOSITION

How much protein should you eat when doing body recomposition? In other words, if you are trying to lose fat and gain muscle mass at the same time? This situation has unfortunately been studied much less frequently than that of bulking and cutting.

According to coach Jeff Nippard, just like in bulk, you can probably suffice with 1.6 g/kg/d, rising to 2.2 g/kg/d the more you are in a calorie deficit and/or the leaner you become ^[ xxxiv ] . After all, ‘recompensation’ often takes place with food at a maintenance level, so that there is no danger of muscle loss if your training is in order.

In summary:
Recommended protein intake recomp: 1.6-2.2 g/kg/d.

DISTRIBUTION AND TIMING OF PROTEINS

Unlike carbohydrates and fats (see below), proteins cannot be stored and preserved until the times when they are most needed. Therefore, with proteins you have to take into account the moment of intake, the amount and the amount of time until the next intake. At least, if you want to be anabolic.

It has been shown that it is best to spread your protein intake evenly throughout the day in ‘shots’ (meals) of 20-40 grams. This is probably the best way to stimulate muscle protein synthesis. In practice, this means that you eat four to five meals a day, with three to four meals in between.

Furthermore, make sure that your training falls between two of those meals so that your body can absorb enough protein both during and after training for the repair and building of muscle tissues.

In summary:
Recommended protein intake per meal: 20-40 g, with an even spread of meals throughout the day.

IN SUMMARY

1. For muscle growth you should eat at least 1.6 grams of protein per kilogram of body weight per day. It’s okay if you eat a little more (for example, if you conveniently stick to 2 g/kg/d), although that normally does not result in extra muscle growth. However, don’t eat too much protein (so more than ~2.2 g/kg/d), because that will unnecessarily be at the expense of your carbohydrate intake. And carbohydrates are also very important for muscle building.

2. With an energy deficit, in the cut, you eat a little more: at least 1.8 g/kg/d. As your fat percentage decreases, you may need even more protein to protect your muscle mass (up to 2.7 g/kg/d). But don’t eat more protein than necessary during the cut, since you already have to cut back enough on carbohydrates due to the calorie restriction.