If you want to know what science says about animal protein vs. plant protein, and which is best for building muscle, then you want to read this article.
Are all types of protein equally good for building muscle?
It depends on whom you ask.
Many vegans and vegetarians will tell you that plant proteins are just as good as animal sources, if not better.
And most hard-shell bodybuilders will laugh that at the idea that you can get big on a plant-based diet.
“How many jacked vegans do you know?” they’ll ask. “Exactly. You gotta eat meat to gain mass, bro.”
Well, who’s right?
Is there something about animal proteins that makes them especially anabolic?
Are plant proteins inherently deficient in some way and unsuitable to muscle building?
And, bottom line, what types of protein should we be eating to gain muscle as efficiently as possible?
Let’s find out.
Table of Contents
Protein is a compound comprised of chains of smaller molecules known as amino acids, which are the basic building blocks of the body.
When you eat protein, your body breaks it down into its constituent parts (amino acids), which are then absorbed and used to create new protein molecules.
These newly formed proteins serve as raw materials for making muscles, ligaments, tendons, hair, organs, and skin, as well various hormones, enzymes, and other chemicals essential to life.
Your body needs twenty-one amino acids to do all of this, and out of them, it must get nine from the food you eat.
These nine are known as “essential amino acids” (EAAs), because they must be obtained from the diet. They are:
The main reason you must eat protein is to provide your body with enough of these essential amino acids to do everything it needs to do.
If you were to somehow strip your diet of all essential amino acids, you’d eventually die.
This is why people that don’t eat enough protein lose muscle faster as they age–their bodies lack the nutrients needed to preserve lean mass.
This is also why regular weightlifting and exercise increases the body’s demand for protein. It damages tissues that must be repaired, and that requires a surplus of amino acids.
A protein’s “amino acid profile” is a breakdown of how much of each type of amino acid that it contains.
Some proteins contain far more of certain amino acids than others, which makes them better or worse for building muscle.
Namely, proteins that have higher amounts of essential amino acids, especially leucine, stimulate more muscle growth than those with less.
There’s a qualitative aspect to protein, too: how well it’s digested, absorbed, and processed by the body.
The easier it is for your body to digest, absorb, and process a protein, the better it’s going to be for gaining muscle.
There are major differences between many animal and plant proteins.
First, there are amino acid profiles.
For example, here’s what 275 calories of steak and broccoli will get you in terms of essential amino acids:
|Essential Amino Acids||Steak||Broccoli|
As you can see, it’s not even close.
You’d have to eat a 18 freaking cups of broccoli to get the essential amino acids found in just 4 ounces of steak.
The story is the same for many other types of plant proteins. Calorie for calorie, they don’t contain anywhere near the amount of essential amino acids as most animal proteins.
This matters a lot when you’re trying to gain muscle, because insufficient EAA intake will hamstring the process.
Furthermore, research suggests that eating several protein feedings per day that each provide at least 3 grams of leucine is ideal for maximizing muscle growth.
Here are a few ways to get to 3 grams of leucine with animal foods:
- ~5 ounces of chicken or beef
- 1 cup of Greek yogurt
- Four eggs
Basically, one to two servings–an amount that anyone can easily eat several times per day.
Here’s what it takes with some of the most leucine-rich plant foods:
- 13 slices of whole wheat bread
- 1 pound of spinach
- 1 1/4 pounds of lentils
- 1 1/2 pounds of peas
Good luck turning that into a meal plan that you actually want to follow.
Anyway, my point is this:
It can be hard to get enough EAAs on a plant-only diet (but not impossible—more on that soon.)
Qualitatively speaking, animal protein is the out and away winner, too.
When scientists talk about “protein digestibility,” they’re referring to the percentage of protein in a food that your body actually absorbs and uses.
For example, if you eat 30 grams of protein and your body ultimately absorbs 27 grams, then that food has a protein digestibility rating of 90%.
Obviously, then, the higher the digestibility score, the better the protein is for building muscle.
Well, research shows that virtually all plants have a protein digestibility score at least 10% lower than animal foods.
For example, meat and fish clock in around 95%, whereas oats and whole wheat bread are closer to 85%, and rice comes in at 75%.
Now, if you’re omnivorous and eat a balanced diet that contains both animal and plant proteins, this won’t be an issue. The majority of your protein will come from animal sources, which will ensure your EAA needs are met.
If, however, you eat plant foods exclusively and don’t do anything to address their deficiencies, you’re less likely to fully meet those needs.
That’s one of the big reasons why studies have shown that omnivores tend to have more muscle than vegetarians and vegans.
It’s not that you can’t build a lean, muscular physique with plant foods alone. It’s just harder to get right than with an omnivorous diet.
That’s also why it’s generally true that animal proteins are better than plant proteins for bodybuilding.
When viewed on the whole, animal proteins contain more essential amino acids per gram, and are better digested and absorbed.
Thus, it’s no surprise that studies show that plant protein doesn’t stimulate muscle growth as effectively as animal protein.
Now, I’ve mentioned several times that none of this means that vegans and vegetarians can’t build muscle as well as omnivores can.
While the literature corroborates the idea that plant eaters are at a disadvantage here, much (if not all) of the deficit can be erased with smart meal planning.
I break down how to do it in my article on vegan bodybuilding.
I should also mention that omnivores should still eat plenty of fruits, vegetables, legumes, and grains.
While protein isn’t their strength, micronutrients are. They contain a large amount of nutrients that are essential to your health and well-being that you can’t get from animal foods.
Regardless of what kinds of protein you eat, you need to eat enough every day to support muscle growth.
So, if you want to gain muscle as quickly as possible, studies show that you need to eat between 0.8 and 1 gram of protein per pound of body weight per day (and slightly more if you’re in a calorie deficit).
An easy way to get the protein you need is to make sure you eat protein at every meal, and to eat 3 top 5 meals per day (research suggests that eating protein more frequently is better for long-term muscle gain).
The best way to ensure you get enough high-quality protein, though, is to learn how to meal plan properly.
“Failing to plan is planning to fail,” right?
Well, that applies to your diet as much as anything else, and this is one of the major reasons most people struggle to gain and lose weight.
Meal plans are the solution.
They allow you to easily meet your macronutritional needs as well as monitor and change your diet to best suit your preferences and goals.
You should also consider using a protein powder (and especially if you want to stick mainly with plant proteins).
A good protein powder is loaded with essential amino acids and is digested and absorbed fantastically well. It’s also more convenient than toting around meals.
If you’re an omnivore, go with a 100% whey isolate protein powder.
This is one of the all-around best sources of protein that you can eat. It’s extremely rich in essential amino acids (and leucine in particular), and it has a very high protein digestibility score.
If you want something plant-based, go with a rice or pea protein powder, or, ideally, a blend of both.
I like these sources because, they’re similar to animal protein in terms of amino acid profile and protein digestibility.
For gaining muscle, animal protein edges out plant protein in several important ways.
It contains higher amounts of essential amino acids and is generally digested and absorbed better.
That doesn’t mean that plant-fueled athletes can’t make gains, though.
They just have to put a bit more thought into their meal planning and choose their sources of protein more carefully.
And regardless of what types of protein you eat, remember that more important is simply eating enough every day. If you eat too little of the highest quality protein, you’ll struggle to gain muscle.