Updated: Oct 8, 2018
The building blocks of protein are amino acids. There are 20 different amino acids necessary for muscle protein synthesis (MPS). Nine of these cannot be synthesised by the body and so need to be consumed in the diet, these are the ‘essential amino acids’ (EAA).
The amount of each amino acid making up total protein content differs from food source to food source. In general, within each gram of protein, animal proteins contain higher levels of all nine essential amino acids, compared to plant proteins. Each plant-based protein is also especially low in particular amino acids, which differ from plant source to plant source. Meaning that to get high enough levels of all nine essential amino acids to maximise MPS, on a completely vegan diet, without consuming unnecessarily high protein or over-consuming calories, it is necessary to combine different plant-based protein sources, and/or to supplement certain amino acids.
Sound difficult? Maybe, but it is certainly not impossible. Don’t give up on it just because it is difficult, you wuss. Yes it is probably more difficult than just eating chicken breast. But it is probably way nicer for the chicken if you figure out how to get what you need just from plants instead. Even if you only do it some of the time.
You don’t need to choose between being massive and muscular or toned and in shape, and being a vegetarian or vegan. To achieve sufficient levels of EAA on a vegetarian diet is not that difficult - you can get all you need for muscle building from dairy and eggs relatively easily, without going over your calorie budget. However a completely vegan diet takes care and strategy. Read on to learn how to meet your protein requirements, and hit optimum levels of all nine essential amino acids, using only plants.
If you are not worried in the science behind it, skip to the 'applications' section at the end of this article for some practical applications in designing an EAA-sufficient vegan diet for maximal MPS.
We say ‘to build muscle you need to eat enough protein’, but really what matters is getting enough of each essential amino acid. If you get 1.8g/kg body weight of daily protein, through animal protein sources, you will naturally get enough of all nine essential amino acids.
Truth: Achieving the optimum amount of each essential amino acid entering the blood will maximise MPS regardless of whether those amino acids come from plants or animal products.
While this is true, it is mistaken to subsequently conclude that as long as you get enough total daily protein, be it from plants or animals, you will be able to maximise MPS.
To get enough of all amino acids to maximise MPS on a vegan diet it is necessary to consume about 30% extra protein compared to an omnivorous diet. This increases further still, if your diet is especially high in fiber. In addition, it is also necessary to pay attention to the combination of different protein sources to achieve the right balance of amino acids. All plant protein sources are ‘complete proteins’, in that they contain all nine of the essential amino acids. However each plant-based protein is especially low in at least one particular amino acid; low enough that in practice, for muscle building, none can be considered a complete protein source.
There are four essential amino acids in particular which need special attention on a vegan diet: leucine, isoleucine, lysine, and methionine. Of these four the lysine requirement for maximal MPS seems to be the most difficult to achieve, then in decreasing order of difficulty, methionine, isoleucine, and leucine.
Leucine is of special significance as it acts to signal the muscle building process and rightly gets a lot of attention in bodybuilding and strength-sport communities. There is a threshold to meet with leucine, in order to maximise the signal for MPS. Leucine is of special importance even on an omnivorous diet, although it is easier to meet the threshold for maximal MPS through animal proteins as they are a little higher in leucine than most plant proteins.
Although leucine is arguably the most important amino acid related to muscle building, it is not too problematic to get enough of on a vegan diet.
Fortunately leucine is present in high enough quantities in all plant based protein sources that it is sufficient to simply get enough protein in each meal without worrying about factoring in different protein sources or supplementation. In young healthy individuals 17 grams of total plant based protein, per meal, is enough to meet the leucine threshold. Which if you are eating four or five meals a day (read this on optimal meal frequency for muscle building) with sufficient total daily protein of 2.4g/kg bodyweight, is not too difficult to achieve.
The leucine requirement to meet the threshold for maximal MPS increases with age, however, and elderly individuals (>65 yrs) on a vegan diet need to consume 53g of total plant protein per meal to meet the leucine threshold, making a lower meal frequency of two or three meals per day, advisable for elderly individuals.
For the remaining three difficult amino acids it requires some tactical combining of different foods to ensure enough of each amino acid is consumed. As all plant proteins are ‘complete proteins’ you could simply consume enough of any single plant-protein source to cover all your bases with just that one protein source, but because any single plant-protein is likely to be low in at least one of these particular essential amino acids, it would require that you consume an unnecessarily high amount of total protein, and likely way too many calories. You could be replacing the unnecessary protein with more fat or carbs instead, for the same total calories.
Fat in particular is an anabolic macro-nutrient, so it would be beneficial to minimize protein requirement as much as possible in order to increase your disposable calories just to be able to spend more on fat. Every two grams of protein you save is almost one extra gram of fat put back into your diet.
Carbs are also tastier, than protein, and generally cheaper by the gram, so there is an impetus to minimize protein requirement to increase disposable calories to spend on carbs too!
All good if you just want to bulk though, and don’t care about getting fat – you could just eat 2kg of peanut butter (12,000 kcal) every day and be sorted for all nine essential amino acids.
How can one best combine plant-protein sources to ensure enough isoleucine, methionine and lysine is consumed for maximal MPS, while optimizing macro nutrient balance and without over-consuming calories?
Legumes and grains are a little lower in isoleucine compared to animal proteins, but seeds are relatively high in isoleucine, close to the amount found in animal proteins. Because isoleucine is still moderately present in legumes and grains, you can still count on getting some of your isoleucine requirement from each of these food sources, but to ensure you get enough, it is best to include some protein from seeds in your daily protein intake. Chia seeds or sunflower protein are a good option.
Seeds, again, seem to be the front-runner in this category, containing more methionine than even some animal proteins (go seeds!), followed by grains – only slightly lower than animal proteins. Whereas legumes have relatively low levels of the methionine. Again arguing the case to include some protein from seeds in your daily intake, while noting that you could also similarly solve this problem by including some grains in your daily protein intake, and you would only need slightly more grain-based protein than seed-based protein to do so.
Lysine is the most difficult EAA requirement to fulfill on a vegan diet. Lysine is highest in legumes out of the plant protein sources, and so it is wise to include some protein from legumes in your daily protein for this reason. Even so, legumes still fall relatively short in lysine content compared to animal proteins. Because lysine is particularly difficult to obtain on a vegan diet, it might be the most worthwhile candidate for supplementation.
By supplementing lysine you can reduce your overall daily protein requirement on a vegan diet from 2.4g/kg bodyweight to 2.1g/kg bodyweight. That’s a saving of 21g of protein (84 kcal) per day for a 70kg person. You could be spending those hard earned calories on fats or carbs instead! 21g of extra carbs is an extra apple a day, or an extra two kiwi fruit. Which you would be pretty glad to have if you were dieting to contest shape.
You can use the following formula to figure out how much lysine to supplement each day:
GRAMS LYSINE = 0.0221 x body weight (in kg***) – 0.0046
For most people this will be between 1 and 3 grams of Lysine daily, depending on your body weight.
Another consideration related to achieving sufficient amino acid levels entering the blood to maximize MPS, on a vegan diet, is fiber consumption. This study found that a higher fibre intake (which is ideal for overall satiety on a diet) decreased protein digestibility. This negatively affects how much protein from your diet actually makes it to into your blood and can be utilized for MPS. To compensate for this, if you are eating more than 25g fiber per day, it is advisable to increase total daily protein to 2.7g/kg bodyweight without lysine supplementation, or 2.4g with lysine supplementation.
For the record, the extra fiber is worth it, if anything only to improve the overall satiety of your diet, but it also confers many other health benefits, and usually leads to a more nutrient rich diet to boot, with all the extra vegetables.
In practice the most realistic way to design an effective vegan diet for muscle gain and fat loss is to combine a high volume of vegetables with legumes, seeds and a blend of vegan protein powders.
Seeds contain a high amount of fat in their whole form and so it is better to rely on getting more of your protein from seeds from the protein powder blend, rather than in their whole form. Legumes are relatively lean when it comes to vegan protein sources and so this makes them the whole food of choice for those wishing to maximize protein without exceeding daily calorie allowance. Vegetables make the diet more satiating or filling (and healthy) and helps prevent binging on foods that will take you away from your goals.
Supplementing the remaining protein means you can reach your daily protein requirement without adding in the extra carbs or fats found in whole food protein sources. Don’t get me wrong, you want your diet to be as whole-food as possible, and to only add in the remaining required protein with a vegan protein powder blend.
Popular vegan protein powders include pea protein (legume) made from split yellow peas, soy protein (legume), rice protein (grain), and hemp protein (seed). You can also find sunflower protein and spirulina as vegan protein powders. A common mix that is relatively high in total protein (about 75%), not too expensive (about the same cost as whey) and covers all the EAA bases, is hemp, rice and pea protein blend. For simplicity the following recommendations will be based around using this particular blend as our vegan protein powder of choice.
For those whose main wish is to lose body fat I recommend eating 1.2kg plus of vegetables per day as the foundation of your diet. Add legumes and vegan protein powder in, around that, in such a way that meets your daily protein requirement without going over your daily calorie target, while making use of as many legumes as possible, only moderate use of seeds, and no grains.
This large amount of vegetables per day will help keep hunger at bay and make dieting easier, as well as being great for overall health. Legumes are more satiating than seeds, as seeds in their whole form have a high fat content, and you will get almost enough protein from seeds from the protein blend. This is also likely to be the most financially friendly way to sculpt your lean vegan body.
For those who are already lean (under 10% body fat for men, under 20% for women) and who wish to prioritize gaining lean muscle mass or shaping their muscles, I recommend basing your diet around 600g of vegetables per day, getting as much of your protein from seeds as you can, with moderate use of legumes, minimal to no grains, and using a vegan protein blend to fill the gap in protein requirement without exceeding your daily calorie target.
Lysine supplementation may become even more desirable for people in this category, if fewer legumes are included, depending on how much protein blend is used.
This being said you could cut or bulk on either of the above strategies; the former will make a lower calorie diet slightly easier by being more filling and is more appropriate for those who find calorie restriction more challenging in general, and the latter would be more appropriate for those who are not as food entrained and can easily manage a less filling diet. Lysine supplementation is an option either way and would still reduce the amount of total daily protein needed in both strategies.
Here are some concrete guidelines to follow, to ensure you get enough of each EAA for maximal MPS:
· 2.4g/kg bodyweight protein per day with lysine supplementation on high fibre diet
· 2.7g/kg bodyweight protein per day without lysine supplementation on high fibre diet
· 2.1g/kg bodyweight protein per day with lysine supplementation on a low fibre diet
· 2.4g/kg bodyweight protein per day without lysine supplementation on a low fibre diet
· At least 66% of total protein should come from seeds and legumes
· At least half of that (33% of total protein) should come from seeds
· Of the remaining 33% of total protein at least 75% of that (25% total protein) should come from grains (if not seeds or legumes) and the rest can come from vegetables
· Make sure every meal contains at least 17g total protein, and increasing with age to 53g or more for individuals over 65yrs
A final note:
Aside from sufficient amino acids, other important considerations for muscle building and general health when on a vegan diet, are vitamin and mineral deficiencies and getting sufficient essential fatty acids (as well as an optimum Omega 3 : Omega 6 ratio). B12, calcium, iron, zinc, the long-chain fatty acids EPA and DHA , and fat-soluble vitamins like A and D, in particular, are likely to become deficient if no strategies are implemented to accommodate for their relative absence in a vegan diet. Supplementation of these essential nutrients is advised, not just for bodybuilders, but anyone on a vegan diet, for optimal health.
Now go sculpt your lean vegan body!