protein combining

Protein Combining: Fact or Fiction?

In today’s world, protein is king. Everywhere you look, everything you read, all signs point towards the message Eat More Protein. There are a number of myths about protein combining for maximum effect. In this article we’ll dig deep to understand whether protein combining is necessary at all.

In the world of diabetes, doctors and nutritionists tell you to eat more protein because it “stabilizes blood glucose” even though the actual research shows just the opposite. In the non-diabetes world, low-carbohydrate diets like the Atkins diet, the Zone diet, the South Beach diet and now the Paleo diet will make you believe that protein and fat are the most important nutrients in your entire diet.

Most importantly, this marketing leads you to believe that if you don’t eat large amounts of protein – especially from meat, fish and dairy products – that your health will suffer, your muscle mass will decrease and you will be more susceptible to disease. And worse off, if you don’t combine your proteins properly, then you’ll die.

Look at the following advertisements to see what I’m talking about:

the perfect protein snack

protein shake

milk protein

perfect guide to protein

self esteem protein


These ads clearly depict beautiful slender women and muscular good looking men eating products loaded with protein. These advertisements are incredibly well done, and very compelling – the problem is that the message Eat More Protein for better health/sex/fitness/weight loss is biologically wrong. Dead wrong.

How Important is Protein?

Eating adequate protein is important, few people will deny that.

Every cell in your body contains protein in the form of enzymes, cell surface receptors, membrane proteins and DNA-protectors. Protein is also found in your blood, saliva, cerebrospinal fluid and urine in the form of hormones, neurotransmitters, urea and antibodies. In addition, your hair, skin and nails are made up of the protein keratin, and your muscle is comprised mainly of actin and myosin proteins.

To say that protein is important is an understatement; protein is very important and 100% required for life.

But here’s where most people go wrong. Many people will tell you that because the infrastructure of your body contains large quantities of protein, your diet must contain large quantities of protein as well. This is exactly where the protein confusion begins.

Proteinaholics (as I like to call them) refer to people who are addicted to eating protein. They make the erroneous assumption that because your body contains a lot of structural protein, that you must also eat a diet high in protein, otherwise you run the risk of wasting away.

Or getting fat. Or having more disease. Or having low self-esteem.

Is any of this true?

Essential vs. Nonessential Amino Acids

There are a total of 20 amino acids that make up most all proteins in mammals. Of these 20 amino acids, 11 are considered nonessential, which means that your body can synthesize them as needed. The other 9 are essential amino acids, which means that you must obtain them from food.

Technically speaking, you only need to find essential amino acids in your food because every tissue in your body can manufacture nonessential amino acids on demand.

Take a look at this image below to get an idea of what this amino acid business is all about. Those with a dashed outline are essential, those with a solid outline are nonessential

amino acids

Protein Combining is Totally Unnecessary

You may have heard one or more of these common protein myths below:

  • Plant proteins are incomplete
  • Plant proteins must be eaten in specific combinations to obtain all essential amino acids
  • A plant-based diet must contain some animal products in order to provide all essential amino acids.

These myths were unintentionally popularized in the book Diet for a Small Planet in 1971, in which the author Frances Moore Lappe stated her theory of protein complementing – a way to eat certain combinations of particular plant foods at the same meal in order to get all of the essential amino acids in the proper amounts.

protein combining

This theory turned out to be completely false, and even though Lappe didn’t mean to promote a false theory, the concept of protein combining spread fast. Lappe later retracted her original statement and in later editions of the same book she clearly states that not only do plant foods contain all essential amino acids, but that humans can easily obtain sufficient protein from plant sources as long as they consumed enough calories.

So in reality, the question of “where do you get your protein?” should actually be “where do you get your calories?”

The problem is that this theory created a longstanding misconception in the minds of people around the planet who adamantly argue that a plant-based diet cannot provide sufficient protein. To convince yourself, simply visit the USDA Food Composition Database (1) and search for any plant food you can think of.

Not only will you will find that every plant food contains all nonessential amino acids, you would also find that eating enough of that single food to meet your calorie requirement would supply more than enough protein for the day.

But let’s be honest – no one actually eats only one food every day. Instead, most people eat a variety of foods in a 24-hour period, and doing so ensures that all essential amino acids are present in sufficient quantities on a daily basis.

Free Amino Acid Pools

You may think that the protein you eat at a single meal is treated differently from the protein that you eat at other meals. Lucky for you, amino acids from multiple meals end up in the same place inside cells. In the water-rich environment inside of cells is where your free amino acid pool resides.

Think of this as a swimming pool of free amino acids that can be used for any purpose necessary.

protein combining

If a chemical reaction inside the mitochondria needs amino acids, they will be transported into the mitochondria to be used for that purpose. Similarly, if a ribosome in the endoplasmic reticulum requires amino acids to synthesize a new cell surface protein, this free amino acid pool provides the building blocks necessary for that to occur.

Now imagine if you ate a meal containing a large amount of corn. Corn is known to have a low amount of lysine, an essential amino acid that cannot be made inside your body. If the theory of protein combining were true, after ingesting this meal high in corn, protein synthesis would stop because lysine would not be available in sufficient quantities.

But we know this is not the case, as sophisticated biological experiments have demonstrated (2,3). Instead, the lysine already present in the free amino acid pool combines with the newly arriving amino acids from corn. In this pool, when all essential amino acids are present, protein synthesis can continue.

Now imagine that you ate a meal containing soy beans the next day, more than 24 hours later. Soy is known to have a high lysine content, and the lysine from this meal would replenish the free amino acid pool inside of cells to compensate for the small amount of lysine eaten previously.

Overall, the nutritional quality of both meals together would provide more than enough essential amino acids, even though they were separated in time. This is one of the main reasons why eating a wide variety of foods is very important for long term health.

Research has now proven that it is not necessary to exceed your protein requirements on a daily basis, and that your average protein intake over the course of multiple days is actually what determines the quantity of essential amino acids (3).


The truth is that even if you ate nothing but plants for the rest of your life, as long as you met your calorie needs, you would not develop a protein deficiency.

But many books, journal articles and medical professionals still promote the message that plant-based diets are insufficient in their protein quantity, even though this has been disproven many times over.

Even though researchers know that it is virtually impossible to design a low fat, plant based whole foods diet deficient in protein (as long as your calorie needs are being met), the theory that plants do not supply enough protein still persists.

Take Home Messages

Protein combining for optimal health and well being is a myth. Don’t believe it.

Leave a Comment Below

Leave a comment below and answer the following question: have you been told to follow the rules of protein combining? What foods did you eat to make this possible?


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  1. NDL/FNIC Food Composition Database Home Page [Internet]. [cited 2016 Jul 12]. Available from:
  2. Bergström J, Fürst P, Vinnars E. Effect of a test meal, without and with protein, on muscle and plasma free amino acids. Clin Sci Lond Engl 1979. 1990 Oct;79(4):331–7.
  3. Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition. Am J Clin Nutr. 1994 May;59(5 Suppl):1203S–1212S.

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About The Author

Cyrus Khambatta

Diagnosed with type 1 diabetes at the age of 22, I have spent over a decade learning the fundamentals of nutrition at the doctorate level. My goal is to share my knowledge of practical nutrition and fitness with people with prediabetes, type 1 and type 2 diabetes. Diabetes is an OPPORTUNITY to attain excellent health. Reversing the effects of insulin resistance can be a fun and enjoyable process if the right system is in place. That's why I've spent over 10 years developing a rock solid system that can minimize blood glucose variability and insulin resistance.

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