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Myth: Plant protein is inferior to animal protein

January 13, 2013

The number one question about the vegan diet, in my opinion, is where do you get your protein.  Click here for my answer!  Once I have answered this question it is usually followed up by a number of comments and many have to do with the quality of plant protein:

“Plant protein is inferior.  Plants do not contain as much protein as animals.  You could never eat enough plant foods to supply all of your protein needs.”  In other words, you will be eating plants all day.  This is incorrect.

“Plant protein is inferior.”  False

The correct term is ‘incomplete’ however incomplete certainly does not mean inferior.

Let’s use a peanut butter sandwich as our example.  But first a quick lesson in protein:

Proteins are made up of amino acids.  Many of them are nonessential which means our bodies are capable of producing them.  Nine amino acids are essential which means we must get these from the foods we eat.  Flesh contains all nine essential amino acids.  Most plants contain seven or eight of the nine thus the term ‘incomplete’.

Since no one would ever eat only one plant food all day, all nine essential amino acids are consumed at each meal.  The common peanut butter sandwich will be our example.  The bread contains the essential amino acids histodine, isoleucine, leucine, lysine, methionine, threonine, tryptophan.  The peanut butter contains the essential amino acids phenylalanine and valine which are the two not present in the bread.  The only essential amino acid not present in peanut butter is histodine but as you can see, that is in the bread.

A peanut butter sandwich is a complete protein, just as complete as the flesh of an animal.  Would you call the separated ingredients of a cake you are baking inferior?  Or is it just an incomplete cake until you combine and bake it?  Once combined you have the whole cake, the same as any other cake.  Protein amino acids work similarly.

According to the textbook Sports and Exercise Nutrition 4rth edition (2013)

  • Eating various plant foods supplies all of the essential amino acids
  • No health or physiologic advantage exists from an amino acid (protein) derived from an animal compared with the same amino acid from vegetable origin.

Animal flesh is packaged with cholesterol and saturated fat.  99% of the time it is also packaged with hormones, antibiotics, and many other additives that are damaging to human health.  This gives plant protein the edge as far as the healthier protein of choice.

“Plants do not contain as much protein as animals”  False

That depends on how you look at it.  A serving of broccoli contains approximately 35 calories and 3 grams of protein.  A serving of ground cow contains approximately 240 calories and 23 grams of protein.  So while one serving of a ground up cow does contain more protein than one serving of broccoli, if you do the math you will find that each contains a little less than one gram of protein per every 10 calories.  Thus the correct statement would be that plants often contain less calories than animals.

This is because carbohydrates frequently make up the balance of calories at 5 calories per gram whereas fats often make up the balance of calories in animals at 9 calories per gram.  Some plants are very high in fat however such as the nut or the avocado.  But unlike animals who contain no carbohydrate, these still contain some complex carbohydrates, essential to optimal human health.

Which leads to the next oven heard comment:

“You cannot eat enough plant foods to provide for all of your protein needs”

When looking at the serving of broccoli compared to the serving of cow this seems to be the case.  But upon further investigation of human protein needs the truth is you can meet all of your protein needs through plant foods alone and easily without having to consume 15 or 20 servings of broccoli per day.  A lesson in adequate protein intake for human health taken from the Sports and Exercise Nutrition book:

  • The average adult male needs 60 grams of protein per day, average female 48 grams
  • Despite the beliefs of many coaches, trainers, and athletes, no benefit accrues from eating excessive protein.
  • With adequate protein intake, consuming animal sources of protein does not facilitate muscle strength or size gains with resistance training compared with protein intake from plant sources
  • Adequate intake of complex carbohydrates is what ensures protein from muscle tissue will not be used as an energy source thus contributing to muscle loss.  Excess protein is not stored and therefore not used to maintain or build muscle later on.
  • Complex carbohydrates should make up 60% of the average person’s diet.
  • During intense training an athlete should consume 70% of their diet as complex carbohydrates.  Therefore it is the carbohydrate, not the protein intake, that should increase for an athlete.  Only during muscle mass building should a person increase their protein to about an extra 10 grams per day.
  • It is recommended that calories from protein represent between 10% and not more than 30% of daily caloric consumption

The healthiest diet for a human being, one that maintains muscle and bone and provides fuel for energy is one that is balanced.  Research shows this balance is 10 to 30% protein and 60% to 70% carbohydrate.

It just so happens that many plants provide this balance while animal flesh does not.  Animal flesh contains only the protein and zero carbohydrate.  It is not balanced.

Let’s revisit our peanut butter sandwich.  The bread is at perfect balance with approximately 70% of its calories from complex carbohydrates and 23% of its calories from protein.  Two slices provide 8 grams of protein.  Two tablespoons of peanut butter provide another 8 grams of protein.  In the case of peanut butter 21% of its calories come from protein and 18% from carbohydrate.  The rest come from fat.  However a fruit spread which is commonly part of a peanut butter sandwich rounds this out to a nice ratio of carbs versus protein.

One peanut butter sandwich at 340 calories provides 16 grams of protein.  For women this is equal to 33% of their daily requirement and 26% for men.

As you can see if a simple common sandwich eaten by millions of people every day can provide this much protein, there is no need for for those on a plant based diet to eat an excessive amount of plant based foods.  Anyone can down a PB and J!

One cup of cheerios with 3/4 cup soy milk provides 10 grams of protein for 130 calories.  Cereal for breakfast and a peanut butter sandwich for lunch equals 26 grams of protein: more than half and nearly half of the protein requirement met for men and women in a simple bowl of cereal and a small sandwich.

Getting enough protein is not a problem for someone who eats a plant based diet.  Actually it is not a problem for anyone in a developed country.

The average person who is free of disease in a developed country will never have a protein deficiency.  This is because protein is in every single food we eat except for oils and a few fruits and the human body only needs approximately 50 to 60 grams per day.  Any extra is not stored as protein for future use as protein to meet any physiological needs which require protein.


Six foot tall boy and cow both made from the same protein source: Plants!

A plant based diet is balanced perfectly for human health.  The protein is not inferior.  And there is no need to consume massive amounts of vegetables to get enough protein.  There is no need to consume servings that are any larger than is normal.  The difference is that all of our servings come from plants.  But our plates and meal sizes are the same.  Where others eat a piece of animal flesh, a salad, and a baked potato we don’t just skip the animal and only eat the salad and potato.  We fill that spot with pasta and veggies and sauce or some other plant based entree.

People forget that it is the carbohydrate that fuels our bodies.  Protein does not make muscles more massive – only strength resistance training can do that.  Protein maintains the muscle we already have along with regular physical use of those muscles.  Without adequate carbohydrate intake the body will use protein for fuel and this may reduce your muscle mass.


(My information comes from nutrition courses taken at Rochester Institute of Technology and the textbooks shown in my first post “Where do you get your protein?”  These classes and books are not based on veganism.  They are objective courses based on research and science intended for students seeking a degree in nutrition.  I highly encourage anyone who has an interest in their own health to purchase these textbooks.)

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