The question of how vegetarians get enough protein is asked all of the time. Sometimes a person will think of a vegetarian as someone who is practically malnourished and worry that they aren’t getting enough protein. Many vegetarians worry if they are getting enough protein.
Protein
Proteins are amino acids. Our bodies can make some of these amino acids and they are called nonessential amino acids. The amino acids that the body cannot make itself are called essential. Americans think they need to eat a ton of protein when they don’t and eat more than they need and much more than is healthy. As a vegetarian the concern is not eating too much, it’s eating too little. When protein is talked about most, it is in the form of protein from animal foods such as beef, pork, poultry, milk and other diary products.
Eating too much protein doesn’t really help a person, since protein cannot be stored in the body. Excess protein is eliminated from the body, and this can cause stress for the kidneys, especially as we age. Eating too much protein has been shown to increase the loss of calcium through the urine. This calcium that is lost is coming from the bones, so too much protein can increase the risk of osteoporosis. Which is ironic since milk is very high in protein, which means drinking too much milk can increase the risk of osteoporosis.
The recommended daily allowance (RDA) for protein is .8 grams per kg of body weight or approximately .365 grams of protein per pound of weight. A 160-pound person would need 58.4 grams of protein per day (160 pounds x .365 grams or 72.7 kg x .8 grams = 58.1 grams per day).
Protein From Plant Foods and Digestibility
When we eat plant foods, the protein isn’t as digestible as it is from animal foods are. To compensate for this, the math then becomes 1 gram of protein per kg of body weight or .45 grams per pound of weight. The 160-pound person eating a strict plant only diet would then need 72 grams of protein from plant food.
For years it was said that in order for a vegetarian to get enough protein, they had to combine certain foods at the same meal in order to get enough of the complete proteins. In a 1997 paper, the American Dietetic Association (ADA) wrote that the conscious combining of different foods at the same meal was unnecessary and that consumption of various amino acids over the course of a day should be fine [2].
Another problem with proteins from plant food is that they are not considered a complete protein. A complete protein is when all 10 essential amino acids are present in that food. That is why it was said that vegetarians should combine foods. For example beans have certain essential amino acids and lack others and brown rice would have these missing essential amino acids, by combining or eating them together, you are then eating a meal with a complete protein.
One plant food that is a complete protein is quinoa. Quinoa is a technically not a grain though many call it a grain since it is a great substitute for grains and rice. It is actually the seed of the goosefoot plant. Quinoa has more protein than any other plant food, twice the protein of rice and five times that of corn.
Lists of plant foods that are high in protein include beans of all kinds. Garbanzo beans, white beans, pinto beans, black beans, kidney and navy beans. Legumes like lentils and peas. Whole grains like barley, brown rice, buckwheat, oatmeal, popcorn, wild rice, millet and whole wheat breads. Seeds and nuts are good sources.
Combining foods could be beans on a whole-wheat tortilla shell, chili with corn bread, black beans and rice, lentil stew with quinoa and hummus (garbanzo beans) on pita bread or a tortilla, hummus comes in all kind of healthy flavors, like garlic hummus.
Soy Protein
Soy is a complete protein. Soy is comparable to the protein in meat. We are able to digest 92% of the protein from meat and 91% from soy [1]. One cup of mature soybeans cooked has almost 29 grams of protein, all essential amino acids. Other soy products would include tofu and TVP (textured vegetable protein), which is dried soy flour. Boiled baby soybeans are also known as edamame and very tasty as a snack or adding to salads.
Lacto Vegetarians
There are several different types of vegetarian diets. Some avoid eggs but eat dairy products and some who eat eggs but avoid dairy products. Either way, eggs and dairy products have a lot of protein and would fill any void in a strict vegan diet. Yogurt can have anywhere from 3 grams to 9 grams of protein per serving and is a healthier way to get protein.
Active Vegetarians
Activity level can increase the need for protein, but still below the average American consumption of protein daily [3]. A balanced vegetarian diet will give you the right amount of protein and without the saturated fat that usually goes along with animal protein. If you are still concerned about the amount of protein you get, you can buy protein powders and make your own protein smoothies. These are either made of soy, whey and more recently hemp.
Sources
[1] Gertjan Schaafsma, “The Protein Digestiblity-Corrected Amino Acid Score,” Journal of Nutrition 130 (2000):1865S-1867S.
[2] The Dietitians Guide to Vegetarian Diets 2nd Edition, Virginia Messina, Reed Mangles, Mark Messina. ISBN 0-7637-3241-9
[3] Dietary Protein Intake Differences Based on Activity Levels Josephine Conolly-Schoonen, MS, RD Published: 03/06/2001
Protein content of select vegan foods
UDSA list of all foods and protein amount sorted alphabetically
