Everyone knows that to build muscle you need to eat a lot of protein: about 1.6 grams per kilogram of body weight per day. But from which food sources can you best get these proteins?

Key points:

1. Whether something is a good source of protein for muscle growth is determined by the protein content, the amino acid profile (biological value) and the digestibility of the protein, and what other nutrients are in the product.

2. To optimally stimulate muscle protein synthesis, the protein source must contain all essential amino acids, preferably with a high content of leucine, the most important amino acid for muscle growth. For optimal muscle growth, you should consume about 2.5 grams of leucine per meal. A larger dose has no further positive effects.

3. Animal protein sources are better at stimulating muscle protein synthesis than vegetable ones. This is due to their higher biological value – including a significantly higher leucine content – and their higher digestibility.

4. The best protein sources are therefore animal: eggs, whey protein, (lean) meat, poultry, fish and dairy.

5. Preferably use regular protein sources (instead of powders) because of the additional nutrients they provide. Use protein powder around your workout if you want.

6. Also eat some vegetable protein, because of the additional fiber, micronutrients and various phytochemicals they provide. Legumes in particular are a healthy and protein-rich food source.

7. To get all the essential amino acids in sufficient quantities as a vegan, you need a little more protein than normal in total – about 20-30% on top of the 1.6 g/kg/d. Even if you only eat vegetable proteins, it is not necessary to combine different protein sources in one meal.

CRITERIA FOR A GOOD PROTEIN SOURCE

To determine whether something is a good protein source, from a bodybuilding perspective, we look at the relative amount of protein the source provides, the composition of those proteins, and the other nutrients the source contains.

1. AMOUNT OF PROTEIN

Muscles are made up of protein, so to grow them, you logically need to eat more protein than normal. Science has now convincingly shown that for muscle growth you need to eat about 1.6 grams of protein per kilogram of body weight per day. That’s about double the normal recommended dose. Eating a little more protein is of course also allowed, but you don’t have to overdo it: more proteins than 1.6 g/kg/d will not give you extra muscle growth (if only that was the case!). The ‘1 gram per pound’ rule (2.2 g/kg/d) that is still floating around on the internet is therefore obsolete.

Other research has taught us, albeit less convincingly, that it is best to take protein in ‘shots’ evenly spread throughout the day. In this way, your muscle protein synthesis, the physiological process underlying muscle growth, would be most optimally stimulated. The recommendation is to spread your daily protein intake over a minimum of four meals, with 20-40 g protein per meal. You plan your training between two meals.

To get that much protein, it makes sense that you choose relatively protein-rich products. Otherwise, you may need to consume far too many calories to meet your protein quota. For example, a banana is a great food, but you will have to eat twenty in a row to get enough protein for one meal…

In summary:
For muscle growth you should eat about 1.6 g of protein per kg of body weight daily, preferably evenly spread over meals with 20-40 g of protein each. To meet these requirements without having to eat excessively many calories, choose relatively protein-rich foods.

2. PROTEIN COMPOSITION

To what extent a protein is effective in stimulating muscle protein synthesis depends on two things: the amino acid profile (also referred to as the biological value) and the digestibility.

AMINO ACID PROFILE

Proteins are made up of amino acids. There are 22 of these building blocks, the so-called essential and non-essential amino acids. The body can make non-essential amino acids itself. Essential amino acids, on the other hand, must be obtained through your diet. To make sure you can do that, make sure you get your protein from a variety of food sources. This is normally no problem with a regular European diet.

The amino acid profile of a protein indicates which amino acids it provides and in what quantities. We call a protein ‘complete’ if it contains all nine essential amino acids.

BCAAS

There are three essential amino acids that are even more important for muscle growth than the others. These are leucine, isoleucine and valine, also known as branched chain amino acids (BCAAs). On the one hand, these amino acids can be used more easily for energy during strength training than other amino acids, and thus counteract muscle breakdown. On the other hand, they form muscle protein by increasing muscle protein synthesis. The BCAAs therefore work both anti-catabolic and anabolic.

Leucine is the most anabolic of all amino acids: it increases muscle protein synthesis the most ^[ i ]^{[ ii ] [ iii ] [ iv ]} . For optimal muscle growth, you should consume about 2.5 grams of leucine per meal. In that respect, proteins with a high leucine content, such as whey protein, have an advantage. However, we should not exaggerate this. As we saw, to maximize muscle protein synthesis, it is recommended to eat 20 to 40 grams of protein per meal. If you do that, you usually easily get 2.5 grams of leucine, even if the leucine content of the protein source is somewhat lower. If you eat 40 grams of whey, you almost get 5 grams of leucine. However, a dose of leucine greater than 2.5 grams provides no additional benefits ^[ v ] .

You may now think that it is enough for muscle growth to consume BCAAs – especially leucine. All the more so since ‘loose’ BCAAs have been a popular bodybuilding supplement for many years. But the latter is not right. BCAAs do their job best in the company of the other amino acids. That is why it is best to consume whole proteins. Supplementing with only BCAAs instead of whole proteins could even be detrimental to muscle growth! Supplementing with leucine alone is therefore also pointless.

BIOLOGICAL VALUE

For muscle growth, it is therefore best to choose proteins with a complete amino acid profile, where a high leucine content is a plus. In other words: you should use proteins with a high biological value.

A high biological value means that there are relatively many essential amino acids in the correct ratio (corresponding to that in the human body). Proteins with a high biological value are seen as high-quality proteins, although that value in itself says nothing about the quality of the protein source and its influence on health (see criterion 2). In fact, it says something about how easily a protein (from food) can be converted into muscle tissue.

DIGESTIBILITY

In addition to the biological value, the digestibility of a protein is also important for muscle growth. By digestibility we mean the proportion of amino acids in the protein that can actually be digested, absorbed and used for protein synthesis.

Nowadays, the PDCAAS (Protein Digestibilty Corrected Amino Acid Score) is increasingly used. This indicates the extent to which a dietary protein can actually meet the need for essential amino acids, taking into account the digestibility of the protein.

NUANCE

We should not exaggerate the importance of the composition of a protein. Most proteins contain a complete amino acid profile, which is why it really won’t make a difference for muscle growth whether you get a little more or less leucine. However, the protein quality may be slightly more important in the hours immediately after training, especially if you are more advanced, which is why bodybuilders often choose whey protein.

In summary:
Sufficient essential amino acids (preferably with a high content of leucine) and good digestibility together determine the protein quality. This is only a small criterion for choosing your protein sources. Since you eat different protein sources in a day, you normally get all the important amino acids in sufficient quantities.

3. PRESENCE OF OTHER NUTRIENTS

In addition to the quality of the proteins themselves, we recommend that you use as many protein sources as possible that also provide other valuable nutrients.

In the first place, the distribution of macronutrients (proteins, carbohydrates and fats) counts for muscle growth. We already saw that you need a lot of proteins, but carbohydrates are in fact just as important for the strength athlete. As a source of energy for strength training, they are much more efficient than fats, let alone proteins. Therefore, choose protein sources that are not too greasy. Something that weighs much more heavily in the cut than in the bulk, because you eat so much in the bulk that your body always has sufficient efficient energy sources.

In addition to the macronutrients, micronutrients (especially vitamins and minerals) also play a role in muscle growth. Admittedly, the ‘macros’ are decisive for muscle growth. Even if you eat mainly unhealthy for some time, you can still build muscle mass. But vitamins and minerals fulfill essential tasks in our body and also contribute to the recovery and construction of muscle tissues. In the long term, it is therefore important that you also eat healthy.

Relatively new is the insight that certain micronutrients can even increase the anabolic power of proteins. For example, research has shown that eating whole eggs stimulates muscle protein synthesis 40% more than eating egg protein alone, which may be due to the cholesterol and other nutrients in the yolk. Other studies also seem to support the idea that regular protein sources can do more for muscle protein synthesis than protein alone (than protein powder) ^[ vi ] . But more on that in a moment.

In summary:
Although the amount of calories is decisive for muscle building, the distribution of macronutrients and to a lesser extent the amount of micronutrients (vitamins and minerals) also play an important role. It is therefore preferable to choose protein sources that contribute to optimizing your ‘macros and micros’.

WHICH PROTEINS ARE THE BEST?

There are two types of protein sources:

animal protein sources (such as dairy, eggs, meat and fish);
vegetable protein sources (such as beans, lentils, tofu, and quinoa).

Which of these two types is best for muscle growth? Well, research shows that animal protein sources are generally better for muscle protein synthesis than vegetable protein ^[ vii ] . According to a publication in the Journal of Nutrition, based on an extensive literature review, there are two reasons for this ^[ vi ] :

Animal proteins have a higher biological value and usually also a higher leucine content. The average leucine content for animal-derived protein foods is ~8-13%. While the average leucine content for plant-based protein foods is ~6-8%. In addition, vegetable protein-rich foods are often deficient in other essential amino acids. So they usually do not have a complete amino acid profile.
Animal proteins usually have a higher digestibility. The average digestibility for animal protein foods is often > 90%. While the average digestibility of vegetable protein foods is ~45-80%. However, vegetable protein powders (such as pea protein powder ) are an exception to this and have a digestibility profile similar to that of animal protein sources (>90%).

The foregoing does not mean that you cannot build optimal muscle as a vegetarian or vegan. Since you normally eat different types of vegetable proteins in a day, you will certainly get all the essential amino acids. In addition, your body always has a supply of amino acids (amino acid pool) that can be used to replenish proteins. So you don’t necessarily have to use different protein sources during one meal. But because vegetable protein sources provide fewer (absorbable) amino acids per protein unit, it is advisable to eat a little more protein in total ^[ viii ] : aim for about 2 g/kg/d as a vegetarian and 2.2 as a vegan. g/kg/d.

In summary:
Animal protein sources are better at stimulating muscle protein synthesis than vegetable sources. This is due to their higher biological value – including a significantly higher leucine content – and their higher digestibility. If you mainly or exclusively eat vegetable protein, eat 20-30% more protein than the regular recommendation to compensate.

If you are not a vegan, we recommend that you get your protein from the following sources.

1. EGGS

Protein from chicken eggs traditionally has the highest biological value, namely 96%. Although it has now been overtaken by whey at this point (see below). Either way, it means that eggs provide you with all the essential amino acids in adequate amounts. Eggs also have a relatively high leucein content: ~0.5 grams. You will then have to eat five eggs at once to get the optimal ‘shot’ of 2.5 grams for muscle protein synthesis. But of course you can also eat other proteins next to it. Eggs also have a high digestibility: 97%.

A (chicken) egg contains an average of 7 grams of protein. 4 grams of this is in the egg white, 3 grams in the yolk. Yes, egg yolks contain protein. Moreover, egg yolk is full of vitamins (including vitamin B12 and vitamin D), minerals (including iron and zinc), antioxidants and healthy fatty acids. These are not or hardly in the egg protein. Egg yolks also contain a lot of cholesterol. That gives eggs a bad name. Wrongly: cholesterol from food has only a limited influence on the cholesterol level in the blood. So there is no reason at all not to eat the egg yolk, as some people sometimes do.

Finally, eggs are also cheap and you can turn them into a tasty meal, whether you do so by boiling, baking or poaching them.

In summary:
Eggs have a high biological value, a relatively high leucine content and a high digestibility. The yolk also contains valuable nutrients that may even enhance the proteins in stimulating muscle protein synthesis.

2. WHEY PROTEIN

Whey protein is obtained from whey that is produced during cheese making. To make hard cheese from milk, the milk must be curdled with a so-called rennet. That rennet contains enzymes that split the milk protein into casein and whey. The casein forms a lumpy mass: curd, the precursor of cheese. The liquid that remains and is squeezed out of the curd is the whey.

Whey is inextricably linked to bodybuilding. Not entirely unjustified, because purely based on criterion 1, whey comes out as the best protein for muscle building by far. Various studies have shown that whey has the highest leucine content and the highest digestibility ^[ vi ] . An average scoop of whey provides you with ~23 grams of protein, of which ~2.5 grams are leucine. The digestibility of whey is 100% (PDCAAS score 1). All amino acids from the protein are thus digested and used for protein synthesis.

Another potential benefit for bodybuilders is that whey is quickly absorbed. It appears in your bloodstream just 15 minutes after ingestion. This makes whey protein the fastest absorbing protein. Not that your body absorbs all the proteins from, for example, one shake at once: it can normally absorb 8 to 10 grams of whey protein per hour. Because of this rapid absorption, whey is often consumed immediately after training. Protein intake in the hours following strength training may have a slightly greater anabolic effec than with recording at later times, although that effect is probably not nearly as great as previously claimed and thought. But it doesn’t help, then it doesn’t harm – on the contrary, because your trusted post-workout protein shake contributes to achieving your daily required protein intake.

Whey is mainly sold in powder form. Easy to quickly prepare a shake and take it anywhere.

However, there is also a disadvantage to using protein powders: they do not provide you with other valuable nutrients, as regular protein sources can. That’s why we recommend that you only use whey powder around your workout and only use regular protein sources for the rest.

While cutting, whey is a good way to get a lot of protein with few calories. An average scoop contains no more than 100 kcal and a scoop of whey isolate, often less. But again, whey powder doesn’t provide micronutrients, so you’ll have to get them from other foods, which is less easy during a calorie-restricted diet. In that case, supplementation of vitamins and minerals can offer a solution.

In summary:
Whey protein has the highest biological value and digestibility and is quickly absorbed. Powdered whey is also easy to carry and quick to consume. The disadvantage is that protein powder usually does not provide other valuable nutrients. That is why you should also use regular protein sources in addition to protein powder.

3. MEAT AND POULTRY

Meat is not only rich in protein, but also in micronutrients not found in many other foods, such as iron, folic acid, selenium, vitamin A and vitamin B12. Meat, like any animal protein, contains a complete amino acid profile and has a relatively high leucine content. The disadvantage of meat, especially pork, is that it also contains a relatively large amount of fat. That’s why you choose the best lean meat, such as beef steak, roast beef steaks or steak tartare.

Poultry, such as chicken and turkey, is just as good a source of protein as meat from other animals and, depending on which piece of bird you choose and if you cook it without the skin, a lot leaner. A piece of chicken or turkey fillet contains about 30 g of protein and about 150-160 kcal. To keep chicken or turkey lean even after cooking, it’s best to grill or steam the piece instead of frying it. If you are already baking it, preferably use olive oil.

In summary:
Meat is rich in proteins and valuable micronutrients. Preferably use lean meats and poultry.

4. FISH

Fish, especially tuna, halibut and salmon, is also an excellent source of protein and provides even fewer calories per gram than poultry. Fish contains little saturated fat and is rich in healthy omega 3 fatty acids, polyunsaturated fatty acids that are good for the heart and brain, among other things. It is not without reason that the Health Council recommends eating fish twice a week (once of which fatty fish such as trout, herring, mackerel, sardines and salmon).

In summary:
Fish is rich in protein and omega 3 fatty acids.

5. DAIRY

Finally, dairy products – milk, yogurt and cheese – are also a good way to get your daily protein. As an animal source of protein, dairy contains all the amino acids necessary for muscle building. For example, the biological value of milk is 91. In addition, dairy is digested quickly; the digestibility of milk is 95%.

The disadvantage of dairy is that the ‘full’ variants contain a relatively large amount of fat. Therefore, it is preferable to choose semi-skimmed or lean products. Low-fat cottage cheese contains the most protein per gram of all dairy products. Half a container (225 g) links almost 30 grams of protein to only 160 kcal.

As a milk product, cottage cheese contains a lot of casein (milk protein), also called ‘slow’ protein, because it takes the body 3-7 hours to break down the protein into amino acids. So if you eat a bowl of cottage cheese right before going to sleep, your body can have amino acids available for almost the entire night. This may help to prevent nocturnal muscle breakdown.

We recommend three servings of dairy a day – for example, two glasses of skimmed milk and a bowl of yogurt or cottage cheese.

In summary:
Dairy has a high biological value and digestibility. Products with casein have a slow absorption rate, so they may offer added value if eaten before a night’s sleep.

6. LEGUMES

Plant proteins are less efficient at stimulating muscle protein synthesis than animal proteins, noted already ^[ vii ] . But that doesn’t mean you should avoid them. On the contrary: we advise you to also include some vegetable proteins in your diet. This on the one hand for sustainability, on the other because of the additional fibres, micronutrients and various phytochemicals that they provide. The latter are bioactive substances that may have a health-promoting effect.

Legumes, such as beans, peas and lentils, are one of the most important non-animal sources of protein. Our personal favorites are kidney beans and chickpeas. Beans have the advantage that you can buy them in cans and heat them quickly in the microwave or in a pan. They provide almost as much protein per serving as a serving of meat, poultry or fish, but contain hardly any fat and are also rich in fiber. If you serve up a large portion of legumes, it is best to skip a meal of meat.

Other high-protein vegetables include green broccoli, spinach, and mushrooms.

As mentioned, if you are vegetarian or vegan, it is best to eat a bit more protein in total.

In summary:
Plant proteins are less efficient at stimulating muscle protein synthesis than animal proteins. Still, you shouldn’t miss them because of the additional fiber, micronutrients and various phytochemicals they provide. Legumes in particular are a healthy and protein-rich food source.

IN SUMMARY

2. To optimally stimulate muscle protein synthesis, the protein source should contain all essential amino acids, preferably with a high content of leucine, the most important amino acid for muscle growth. For optimal muscle growth, you should consume about 2.5 grams of leucine per meal. A larger dose has no further positive effects.