Muscles are important.
The more you have, the greater your quality of life.
Muscles carry out many vital functions, such as breathing, walking, talking and lifting boxes.
They burn calories, allowing you to eat a little bit more without getting fat.
Plus… having a respectable amount of muscle mass can help you look great naked.
If you want to build and maintain muscle, you somehow need to ingest the building blocks that they are made of. Makes sense, right?
Well… the best way to ingest the building blocks of muscle is to eat muscle. In other words, eat meat.
Here are 5 nutrients in animal foods that are important for muscle mass, that can’t be obtained from plants.
Creatine is the most popular muscle building supplement in the world.
A plethora of scientific studies show that it can improve strength and increase muscle mass (1).
The way creatine works, is that it forms an energy reserve in the muscles.
The energy currency of every cell on the planet is called ATP, or Adenosine Triphosphate.
I don’t want to get into the complex biochemistry, but ATP produces energy by donating a phosphate molecule. When it does that, energy is released.
The problem is that cells only have a finite amount of ATP in them and it doesn’t last very long if you’re doing tough exercises like squats.
That’s where creatine steps in. Creatine carries phosphate in the muscle cells and donates them to ATP so the cell can continue to produce energy.
This is particularly important during high intensity anaerobic work like lifting weights or sprinting.
The body can produce its own creatine, but this process is inefficient.
About 95% of the creatine in the body is stored in muscle cells and the only good dietary sources of creatine are animal products.
Creatine is also concentrated in the brain. Studies show that vegetarians, but not meat eaters, see improvements in brain function with creatine supplementation. This is another indicator of creatine deficiency in vegetarians (4, 5).
Bottom Line: Animal foods are the only good sources of creatine in the diet. Studies on vegetarians show that they are deficient in creatine, which can adversely affect function of both muscle and brain.
2. Animal Protein
Muscles are made largely of proteins, which are long strings of amino acids, folded into complex shapes.
There are 21 amino acids that the body uses to synthesize proteins.
The body can produce some of them, while it must get others from the diet. The ones the body can not produce are termed essential amino acids (EAAs).
To make full use of the protein in the diet, we need to get all the essential amino acids in the right ratios.
The proteins in animal foods like meat, eggs, fish and dairy contain all the essential amino acids and can easily be incorporated into body proteins. The same can not be said for plant proteins, which do not have an optimal amino acid profile (6).
Studies show that consumption of animal protein is positively associated with muscle mass and that an omnivorous diet causes greater muscle gain during resistance training than a vegetarian diet (7, 8, 9).
The RDA for protein in the diet is very low, set at 0.8 grams protein for each kilogram of body weight, or 0.36 gram per pound.
This makes it difficult to satisfy the body’s protein needs on a plant-based diet, because most plants are very low in protein.
Bottom Line: The best sources of protein in the diet are animal foods. It is extremely difficult to consume enough protein on a strict plant-based diet.
Carnosine is a dipeptide that is highly concentrated in muscle and the brain.
It is formed out of two amino acids, histidine and beta-alanine.
One of the reasons our muscles fatigue during intense work is that they form large amounts of lactic acid, which increases the acidity of the muscle cell and hinders its function.
This is where carnosine steps in… it functions as a buffer against acid buildup.
Vegetarians have less carnosine in their muscles than meat eaters, which should lead to increased muscular fatigue (19).
Bottom Line: Carnosine is found strictly in animal foods. It reduces acid buildup in muscles and leads to reduced fatigue in the muscles. Vegetarians are deficient in carnosine.
4. Vitamin D3
A deficiency in Vitamin D is widespread, especially in countries where there is little sun.
Vitamin D actually functions as a steroid hormone in the body, where it travels into the nuclei of cells to turn genes on or off.
Having adequate Vitamin D in the bloodstream is important for many reasons, but one of them is proper function of muscles.
There are two forms of Vitamin D in the diet… D2 (ergocalciferol) and D3 (cholecalciferol). D2 comes from plants, D3 from animals.
The animal form (D3) is much more active in the body than D2 (26).
The only good food sources are cod fish liver oil and fatty fish. If you don’t get much sun throughout the year, it may be best to take a D3 supplement.
Bottom Line: Vitamin D3 is a very important vitamin, with a deficiency being linked to poor muscle function. Vitamin D3 can be found in limited amounts in animal foods.
5. Saturated Fat and Cholesterol
Many people still think that saturated fat and cholesterol are the root of all evil, despite it having been thoroughly disproven.
This has led many people to adopt a low-fat diet, which is low in animal foods, but high in sugars and starches.
One study shows that consumption of saturated fat is correlated with increased testosterone levels (29).
Eat Some Animals… or Take Supplements
There are many other nutrients that are critical for health but lacking in plant-foods. One example is Vitamin B12.
If you choose to avoid animals but want to build or maintain muscle, then I highly recommend that you supplement.
I don’t doubt that vegan diets can lead to weight loss, but over the long term they may lead to significant muscle loss as well.