” I submit that scientists have not yet explored the hidden possibilities of the innumerable seeds, leaves and fruits for giving the fullest possible nutrition to mankind.” – Mahatma Gandhi
Every protein molecule consists of a chain of amino acids. An essential amino acid is one that cannot be synthesized by the body, and therefore must be supplied as part of the diet. Humans must include adequate amounts of 9 amino acids in their diet.
In his book, The China Study, Professor T. Colin Campbell shows that the U.S. RDA for protein is greatly overestimated. Studies of the diets of chimpanzees compared to that of humans confirm the same truth. “Chimpanzees maintain a fairly low and constant protein intake …”
I have looked at the nutritional content of dozens of various green vegetables and I was pleased to see that the aminos that were low in one plant were high in another. In other words, if we maintain a variety of greens in our diet, we will cover all essential aminos in abundance.
I decided to calculate by myself the essential amino acid content in one big bunch of kale and one big bunch of lambsquarters (a weed). I have chosen kale because it is available in most produce markets. Lambsquarters is one of the most common edible weeds that grows in different climates. Most farmers should be able to identify lambsquarters for you.
I then compared the numbers that I got with the amounts of essential amino acids for an average adult recommended by USDA. For more information on the content of Essential Amino Acids in Lambsquarters and Kale, please see page 43 in my book Green For Life
The resulting numbers demonstrated that dark green leafy vegetables contain similar or larger amounts of amino acids than the Recommended Daily Allowance (RDA). However, because of the confusion between vegetables (roots) and greens, we are told that vegetables, including greens, are a poor source of amino acids. This inaccurate statement has led to the malnourishment and suffering of people for decades. The lack of research on the nutritional content of greens has led to a great confusion among the majority of people, including many professionals. Dr. Joel Fuhrman wrote in his book Eat to Live: “Even physicians and dietitians… are surprised to learn that …when you eat large quantities of green vegetables, you receive a considerable amount of protein.”
Where do I get my protein? Being aware of the confusion around vegetables, I understand why this became a popular question. Since most people were not aware that greens have an abundance of readily available essential amino acids, they were trying to eat from the other food groups known for their rich protein content. However, let me explain the difference between complex proteins found in meat, dairy, fish, etc. and individual amino acids, found in fruits, vegetables, and especially in greens.
It is clear that the body has to work a lot less when creating protein from the assortment of individual amino acids from greens, rather than the already combined, long molecules of protein, assembled according to the foreign pattern of a totally different creature such as a cow or a chicken. I would like to explain the difference between complex proteins and individual amino acids with a simple anecdote.
Imagine that you have to make a wedding dress for your daughter. Consuming the complex proteins that we get from cows or other creatures is like going to the second hand store, and buying many other people’s used dresses, coming home and spending several hours ripping apart pieces of the dresses that you like and combining them into a new dress for your daughter. This alternative will take a lot of time and energy and will leave a great deal of garbage. You could never make a perfect dress this way.
Consuming individual amino acids is like taking your daughter to a fabric store to buy beautiful new fabric, lace, buttons, ribbons, threads, and pearls. With these essential elements you can make a beautiful dress that fits her unique body perfectly. Similarly, when you eat greens, you “purchase” new amino acids, freshly made by sunshine and chlorophyll, which the body will use to rebuild its parts according to your own unique DNA.
Contrary to this, your body would have a hard time trying to make a perfect molecule of protein out of someone else’s molecules, which consist of totally different combinations of amino acids. Plus, your body would most likely receive a lot of unnecessary pieces that are hard to digest. These pieces would be floating around in your blood like garbage for a long time, causing allergies and other health problems. Professor W. A. Walker from the Department of Nutrition at the Harvard School of Public Health, states that, “Incompletely digested protein fragments may be absorbed into the bloodstream. The absorption of these large molecules contributes to the development of food allergies and immunological disorders.” 
The ironic result of consuming this imperfect source of protein, (animal protein), is that many people develop deficiencies in essential amino acids. Such deficiencies are not only dangerous to health, but they dramatically change people’s perceptions of life and the way people feel and behave. The body in producing neurotransmitters uses some essential amino acids, like tyrosine, tryptophan, glutamine, histamine, and others. Neurotransmitters are the natural chemicals that facilitate communication between brain cells. These substances govern our emotions, memory, moods, behavior, learning abilities and sleep patterns. For the last three decades, neurotransmitters have been the focus of mental health research.
According to the research of Julia Ross, a specialist in nutritional psychology, if your body lacks certain amino acids, you may develop strong symptoms of mental and physiological imbalance and severe cravings for unwanted substances.
For example, let us consider tyrosine and phenylalanine. The symptoms of a deficiency in these amino acids can cause:
- Lack of energy
- Lack of focus and concentration
- Attention deficit disorder
In addition, the symptoms of a deficiency in these amino acids may lead to cravings for:
Using available data from official sources  I have calculated the amounts of these two essential amino acids that we can receive from either chicken or dark green endive:
One serving: One head:
222 mg tyrosine 205 mg tyrosine
261 mg phenylalanine 272 mg phenylalanine
As you can see, contrary to the popular opinion, there are plenty of high quality proteins in greens. According to the explanation of Professor T. Colin Campbell, “There is a mountain of compelling evidence showing that so called “low-quality” plant protein, which allows for slow but steady synthesis of new proteins, is the healthiest type of protein.” For example, the protein from greens doesn’t have cancer as a side effect. Yet, in many books, greens are not even listed as a protein source because greens have not been researched enough.
Greens have sufficient protein to build muscle in grazing animals. I received this testimony from my very first American friend, a farmer with a BA in psychology from Harvard University, Peter Hagerty of Maine: “When our sheep are in the barn eating concentrated feed such as ground corn and oats, they gain weight much more quickly, but young lambs, once they reach 120 lbs or 90 % of slaughter weight, begin putting this concentrated food into fat rather than muscle which is not advantageous for the consumer who has to trim this fat off and throw it away. If the lambs are grass fed, they grow more slowly but they can reach full slaughter weight with very little fat. So my observations are: concentrates seem to put on easily burnable fats and grasses put on quality muscle.”
In summary, greens provide protein in the form of individual amino acids. These amino acids are easier for the body to utilize than complex proteins. A variety of greens can supply all the protein we need to sustain each of our unique bodies.
As a recommendation, I invite everyone to try green smoothies, the most pleasant and palatable way to consume greens I have found to date. Get your protein and enjoy!
Nancy Lou Conklin-Brittain, Richard W. Wrangham, Catherine C. Smith, Relating Chimpanzee Diets to Potential Australopithecus Diets, Department of Anthropology, Harvard University, Cambridge, MA. 1998.
 Data from Average Adult Male, Age 19-31, Weight 170 lbs. Source: National Research Council, “Protein and Amino Acids,” in Recommended Dietary Allowances, 10th edition (1989); USDA SR17
 Walker WA, Isselbacher KJ. Uptake and transport of macro-molecules by the intestine. Possible role in clinical disorders. Gastroenterology: 67:531-50, 1974
 Ross, Julia, M.A. The Diet Cure. New York: Penguin Books. 1999.
 U.S. Department of Agriculture, Agricultural Research Service. 2005. USDA National Nutrient Database for Standard Reference, Release 18
 Campbell, T. Colin, Ph.D. The China Study. Texas: Benbella Books 2004.