It is very easy for a vegan diet to meet the recommendations for protein, as long as calorie intake is adequate. Strict protein combining is not necessary; it is more important to eat a varied diet throughout the day.
Some Americans are obsessed with protein. Vegans are bombarded with questions about where they get their protein. Athletes used to eat thick steaks before competition because they thought it would improve their performance. Protein supplements are sold at health food stores. This concern about protein is misplaced. Although protein is certainly an essential nutrient which plays many key roles in the way our bodies function, we do not need huge quantities of it. In reality, we need small amounts of protein. Only one calorie out of every ten we take in needs to come from protein 1. Athletes do not need much more protein than the general public 2. Protein supplements are expensive, unnecessary, and even harmful for some people.
How much protein do we need? The RDA recommends that we take in 0.8 grams of protein for every kilogram that we weigh (or about 0.36 grams of protein per pound that we weigh) 1. This recommendation includes a generous safety factor for most people. When we make a few adjustments to account for some plant proteins being digested somewhat differently from animal proteins and for the amino acid mix in some plant proteins, we arrive at a level of 1 gram of protein per kilogram body weight (0.45 grams of protein per pound that we weigh). Since vegans eat a variety of plant protein sources, somewhere between 0.8 and 1 gram of protein per kilogram would be a protein recommendation for vegans. If we do a few calculations we see that the protein recommendation for vegans amounts to close to 10% of calories coming from protein. [For example, a 79 kg vegan male aged 25 to 50 years could have an estimated calorie requirement of 2900 calories per day. His protein needs might be as high as 79 kg x 1 gram/kg = 79 grams of protein. 79 grams of protein x 4 calories/gram of protein = 316 calories from protein per day. 316 calories from protein divided by 2900 calories = 10.1% of calories from protein.] If we look at what vegans are eating, we find that between 10-12% of calories come from protein 3. This contrasts with the protein intake of non-vegetarians, which is close to 14-18% of calories.
So, in the United States it appears that vegan diets are commonly lower in protein than standard American diets. Remember, though, with protein, more (than the RDA) is not necessarily better. There do not appear to be health advantages to consuming a high protein diet. Diets that are high in protein may even increase the risk of osteoporosis 4 and kidney disease 5.
Table 1: Sample Menus Showing How Easy It Is To Meet Protein Needs
Breakfast: 1 cup Oatmeal 6
1 cup Soymilk 7
1 Bagel 9
Lunch: 2 slices Whole Wheat Bread 5
1 cup Vegetarian Baked Beans 12
Dinner: 5 oz firm Tofu 11
1 cup cooked Broccoli 4
1 cup cooked Brown Rice 5
2 Tbsp Almonds 4
Snack: 2 Tbsp Peanut Butter 8
6 Crackers 2
TOTAL 73 grams
Protein Recommendation for Male Vegan [based on 0.8-1 gram of protein per kilogram body weight for 70 kilogram (154 pound) male] 56-70 grams
Breakfast: 2 slices Whole Wheat Toast 5
2 Tbsp Peanut Butter 8
Lunch: 6 oz. Soy Yogurt 6
2 Tbsp Almonds 4
1 Baked Potato 4
Dinner: 1 cup cooked Lentils 18
1 cup cooked Bulgur 6
Snack: 1 cup Soymilk 7
TOTAL 58 grams
Protein Recommendation for Female Vegan [based on 0.8-1 gram of protein per kilogram body weight for 57.5 kilogram (126 pound) female] 46-58 grams
Additional food should be added to these menus to provide adequate calories and to meet requirements for nutrients besides protein.
Table 2 shows the amount of protein in various vegan foods and also the number of grams of protein per 100 calories. To meet protein recommendations, the typical adult male vegan needs only 2.5 to 2.9 grams of protein per 100 calories and the typical adult female vegan needs only 2.1 to 2.4 grams of protein per 100 calories. These recommendations can be easily met from vegan sources.
Table 2: Protein Content of Selected Vegan Foods
FOOD AMOUNT PROTEIN(gm) PROTEIN(gm/100 cal)
Tempeh 1 cup 41 9.3
Seitan 3 ounces 31 22.1
Soybeans, cooked 1 cup 29 9.6
Lentils, cooked 1 cup 18 7.8
Black beans, cooked 1 cup 15 6.7
Kidney beans, cooked 1 cup 13 6.4
Veggie burger 1 patty 13 13.0
Chickpeas, cooked 1 cup 12 4.2
Veggie baked beans 1 cup 12 5.0
Pinto beans, cooked 1 cup 12 5.7
Black-eyed peas, cooked 1 cup 11 6.2
Tofu, firm 4 ounces 11 11.7
Lima beans, cooked 1 cup 10 5.7
Quinoa, cooked 1 cup 9 3.5
Tofu, regular 4 ounces 9 10.6
Bagel 1 med.
(3 oz) 9 3.9
Peas, cooked 1 cup 9 6.4
Textured Vegetable Protein (TVP), cooked 1/2 cup 8 8.4
Peanut butter 2 Tbsp 8 4.3
Veggie dog 1 link 8 13.3
Spaghetti, cooked 1 cup 8 3.7
Almonds 1/4 cup 8 3.7
Soy milk, commercial, plain 1 cup 7 7.0
Soy yogurt, plain 6 ounces 6 4.0
Bulgur, cooked 1 cup 6 3.7
Sunflower seeds 1/4 cup 6 3.3
Whole wheat bread 2 slices 5 3.9
Cashews 1/4 cup 5 2.7
Almond butter 2 Tbsp 5 2.4
Brown rice, cooked 1 cup 5 2.1
Spinach, cooked 1 cup 5 13.0
Broccoli, cooked 1 cup 4 6.8
Potato 1 med.
(6 oz) 4 2.7
Sources: USDA Nutrient Database for Standard Reference, Release 18, 2005 and manufacturers’ information.
The recommendation for protein for adult males vegans is around 56-70 grams per day; for adult female vegans it is around 46-58 grams per day (see text).
It is very easy for a vegan diet to meet the recommendations for protein. Nearly all vegetables, beans, grains, nuts, and seeds contain some, and often much, protein. Fruits, sugars, fats, and alcohol do not provide much protein, so a diet based only on these foods would have a good chance of being too low in protein. However, not many vegans we know live on only bananas, hard candy, margarine, and beer. Vegans eating varied diets containing vegetables, beans, grains, nuts, and seeds rarely have any difficulty getting enough protein as long as their diet contains enough energy (calories) to maintain weight. [See the sections on Pregnancy, Lactation, and Infants and Children (pages 176-197 in Simply Vegan, 4th edition) for details about protein needs during these special times.]
What about combining or complementing protein? Doesn’t that make the protein issue much more complex? Let’s look at a little background on the myth of complementing proteins. Protein is made up of amino acids, often described as its building blocks. We actually have a biological requirement for amino acids, not for protein. Humans cannot make nine of the twenty common amino acids, so these amino acids are considered to be essential. In other words, we must get these amino acids from our diets. We need all nine of these amino acids for our body to make protein.
Some people say that eggs, cow’s milk, meat, and fish are high quality protein. This means that they have large amounts of all the essential amino acids. Soybeans, quinoa (a grain), and spinach also are considered high quality protein. Other protein sources of non-animal origin usually have all of the essential amino acids, but the amounts of one or two of these amino acids may be low. 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.
Frances Moore Lappe, in her book Diet for a Small Planet 6 advocated the combining of a food low in one amino acid with another food containing large amounts of that amino acid. This got to be a very complicated process, with each meal having specific amounts of certain foods in order to be certain of getting a favorable amino acid mix. Many people got discouraged with the complexity of this approach. Actually, Lappe was being overly conservative to avoid criticism from the “Nutrition Establishment.” She has since repudiated strict protein combining, saying, “In combating the myth that meat is the only way to get high quality protein, I reinforced another myth. I gave the impression that in order to get enough protein without meat, considerable care was needed in choosing foods. Actually it is much easier than I thought” 7.
Table 3: Amounts of Foods Providing Recommended
Amounts of Essential Amino Acids
12-1/3 cups of cooked corn OR 6-1/2 large potatoes OR 2-1/2 cups of tofu OR 15-1/2 cups of cooked brown rice
Any one of the above foods, eaten in the amount specified, would provide the recommended ammounts of all essential amino acids for an adult male. Women would need about 20% less of each food due to lower recommendations. This concept is illustrated below:
Food Try Thr Iso Leu Lys Met+Cys Phe+Tyr Val
Adult RDA,154 lb male 1 350 1400 1330 2940 2660 1330 2310 1680
12-1/3 cups corn 443 2521 2521 6777 2660 1820 5326 3616
6-1/2 large potatoes 760 1768 1963 2940 2951 1365 3946 2743
2-1/2 cups tofu 780 2045 2480 3808 3298 1333 4112 2530
15-1/2 cups cooked rice 899 2573 2960 5766 2666 2418 6231 4108
Source: USDA Nutrient Database for Standard Reference, Release 18, 2005.
Notes: Amounts of amino acids are in milligrams.
We recommend 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 8,9.
Even if you ate only one food and not the variety of foods typical of a vegan diet, you would probably get enough protein and essential amino acids. Remember, almost all protein sources of non-animal origin contain all of the essential amino acids. You would have to eat a lot of the protein source (if there was only one source of protein in your diet) to meet essential amino acid needs. Table 3 shows the amounts of various foods an adult male would have to eat if he relied on a single food source for his protein needs. Females would need about 20% less of each food due to the lower protein recommendation for women.