Vegetarianism & Protein

Amino acids are the building blocks of protein. Twenty amino acids are needed to build the various proteins used in the growth, repair, and maintenance of body tissues. The building of good protein is determined by how well the amino acids in the foods we eat are utilized. The absence of one amino acid halts protein synthesis completely. Eleven of these amino acids can be made by the body itself, while the other nine (called essential amino acids) must come from the diet. The classification of an amino acid as essential or nonessential does not reflect its importance, because all twenty amino acids are necessary for health. Instead, this classification system simply reflects whether or not the body is capable of manufacturing a particular amino acid. A protein source that contains all of these nine essential amino acids, in sufficient quantities, is called complete. These protein sources may or may not contain all of the nonessential amino acids. Respectively, a protein that low in one or more of the nine essential amino acids is called incomplete. Eggs, cow’s milk, meat, and fish have been designated as high quality protein. This means that they have large amounts of all the essential amino acids and are complete proteins. Many plant proteins are considered incomplete and are lower quality proteins than animal products because they are low in one or more of the nine essential amino acids (particularly lysine, methionine, and tryptophan).37

For example, grains are lower in lysine (an essential amino acid) and legumes are lower in methionine (another essential amino acid) than those protein sources designated as high quality protein. Particularly if you avoid all complete protein food sources, focus on eating a variety of unrefined grains, legumes, seeds, nuts, and vegetables throughout the day, so that if one food is low in a particular essential amino acid, another food will make up this deficit.38



It used to be thought that different kinds of plant foods had to be eaten together at the same meal in order to get a “complete protein” (meaning all the essential amino acids; see protein terms). This turned being a vegetarian into a nutritional jigsaw puzzle. Which pieces fit together? Nutritionists have now concluded that the body is smart enough to combine proteins on its own. The body takes in all the plant proteins consumed in a day and puts the amino acid puzzle together to build the complete proteins that it needs.


Individual needs

To give you a ballpark figure with which to work, divide your weight by 2.2. That is how many grams of protein that may be appropriate for you. However, because many factors affect optimal protein intake, the best way to determine how much protein you should eat is to experiment with different amounts and see how you feel. Common symptoms that can signal a need to eat more protein (and fewer carbohydrates such as breads, sugars, and starches) include fatigue, poor mental focus, frequent susceptibility to illness, yeast overgrowth, bloating, inability to lose weight, premenstrual syndrome, and sugar and carbohydrate cravings.39

Listen to your body and find your optimal range. Most people do best with 10%-30% of their daily calories coming from protein.


Protein in common foods

Food Quantity Protein in Grams
Avocado 1 3 ¼ inch diameter 5
Soybeans, cooked 1 cup 29
Black beans, cooked 1 cup 15
Kidney beans, cooked 1 cup 13
Chick peas, cooked 1 cup 12
Pinto beans, cooked 1 cup 12
Lentils, cooked 1 cup 18
Blackeyed peas, cooked 1 cup 11
Lima beans, cooked 1 cup 10
Tofu, firm 4 oz. 11
Tempeh ½ cup or 4 ounces 17
Nutritional yeast 1 Tablespoon 8
Nuts ¼ cup 2-7
     Almonds, Cashews ¼ cup 7
     Peanuts, Pumpkin seeds ¼ cup 10
     Peanut butter 1 Tablespoon 4
Seeds 1 ounce 6
     Sunflower seeds ¼ cup 9
Oatmeal, cooked 1 cup 6
Rice, cooked 1 cup 6
Quinoa 1 cup cooked 9
Bread One slice 2-3
Peas 1 cup 9
Fruit One apple, banana, orange, etc. 1
Miso 1 ounce 2
Vegetables 1 cup raw or ½ cup cooked 2-3
Buttermilk 1 cup 8
Cheese, firm 1 ounce 6-10
Cheese, soft 1 ounce 2-4
Cottage cheese 1 cup 30
Eggs One 6-7
Kefir 1 cup 9
Meat, poultry, fish 3-3 ½ ounces 17-27 (1 oz = approx 7 grams)
Milk 1 cup 8-9
Yogurt 1 cup 8-9


Here are several studies and comments (by Dr Mercola and Dr. Byrnes) to studies that may be of interest to those concerned about excess protein.


Protein In Diet May Reduce Heart Disease Risk

Replacing some carbohydrate intake with protein may actually reduce the risk of ischemic heart disease. The research teams, from the Harvard School of Public Health, compared the diets of people in different countries to the rates of heart disease After controlling for age, the investigators determined that a higher intake of total protein was associated with a lower risk of ischemic heart disease.

American Journal of Clinical Nutrition August 1999;70:221-227.

Dr Mercola’s Comment: Now we have research from the Halls of Harvard showing that more protein will actually reduce, NOT increase, heart disease as is commonly purported. Vegetarians take note: it is exceedingly difficult to obtain adequate protein levels without obtaining animal protein. The authors also do not address the more obvious reasons why increased protein lowers heart disease. Protein is usually associated with fat, so if one consumes more protein, one must reduce their carbohydrate intake. This usually means one then consumes a lesser amount of grains. And, as readers of this newsletter are familiar with, increased grains are one of the major negative influences on all chronic illness.

Found at


High Protein Diet Found Beneficial

Contrary to what many conventional medical authorities, vegetarians, and other promoters of low-fat diets say, consumption of very high levels of protein may not have adverse effects and may in fact boost antioxidant levels, new research from Germany has found. Since “The maximum dietary protein intake that does not cause adverse effects in a healthy population is uncertain,” as the researchers note, they decided to test their theory that increased protein consumption would induce greater oxidative stress in order to determine this threshold of protein consumption at which adverse effects could be seen.

Researchers performed tests on laboratory rats, splitting them up into groups receiving one of three different levels of dietary protein:

  • 14% of total calories
  • 26% of total calories
  • 51% of total calories

After 15 weeks of feeding on the specific protein level diets, various parameters of antioxidant status were measured. Much to the authors surprise, it was found that the groups consuming the higher protein diets had better antioxidant parameters than the lower protein diets, such as reduced lipid peroxide levels.

“Long-term intake of high protein diets did not increase variables of oxidative stress, in contrast to our initial hypothesis,” the authors concluded. “An unexpected finding was that adequate (14%) protein feeding may in fact induce oxidative stress,” they add.

Journal of Nutrition 2000; 130: 2889-2896

Dr. Mercola’s Comment: Further evidence that low-fat, vegetarian, and vegan diets are not the healthiest choices for most people. These diets are almost invariably lower in protein than diets containing animal proteins. Probably the best single source of protein are eggs, but it is best to purchase organic eggs from free-range chickens.

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Dr. Byrnes’s Comment: The Dangers of Low Protein/Fat Diets. Especially post-menopausal women, are told to eat a lower protein diet because of the common (incorrect) belief that protein intake causes calcium loss and, hence, osteoporosis. Well, much to their surprise, German researchers recently discovered that rats fed a higher protein diet had LESS free radical activity than rats fed a low protein diet! “Free radicals” are renegade molecules that can cause DNA mutations and cell damage. They are highly operative in the appearance of many diseases.

What you need to realize is that the SOURCE of your protein foods needs patrolling: fractionated protein powders (like soy “shakes”) that have been denatured through high heat processing and lack fat-soluble vitamins should be avoided. Get your protein from REAL food. And be sure to eat it with its fat to get those fat-soluble nutrients. This means not trimming the fat off your meats and not removing the skin from your poultry products. You should also realize that, as you increase your intake of natural saturates (like butter, coconut oil, and beef/lamb fat), your body’s available supply of antioxidants (which neutralize free radicals) is increased as saturates do not require antioxidants to keep them from going rancid in the body (unlike polyunsaturated vegetable oils).

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