Lesson 14.11: Getting Enough Protein?

By Vesanto Melina, RD, www.nutrispeak.com

How much protein do vegan and lacto-ovo vegetarian adults need?

The recommended protein intake (RDA) for adults is 0.8 grams protein per kilogram of body weight per day (g/kg/day).[1] This RDA includes a significant safety margin and exceeds the needs of most people.

Although the RDA is not different for those who choose vegetarian, vegan and raw food diets, many experts recommend 0.9 g protein/kg/day to compensate for the slightly decreased bioavailability of the protein in plant foods. Thus recommended protein is as follows:

Body weight in pounds Body weight in kilograms Recommended Daily Protein
120 lb 54 kg 49 grams
135 lb 61 kg 55 grams
150 lb 68 kg 61 grams
165 lb 75 kg 68 grams
180 lb 82 kg 74 grams
195 lb 88.5 kg 80 grams

Here’s another way to express protein recommendations: At least 10% of the calories you consume should be derived from protein (and, of course, you should eat sufficient calories).

Two leading health organizations, the World Health Organization and the Institute of Medicine, provide similar guidelines regarding the optimal distribution of protein, carbohydrate, and fat in the overall diet.

Blending these guidelines suggests that you should aim for 10% to 20% of your calories from protein, 50% to 75% of your calories from carbohydrate, and 15% to 30% of your calories from fat.[1], [2]

Studies conducted since 1982 show average vegan protein intakes to be in the range of 10% to 12% of calories. Since 2000 there have been fifteen studies on vegans who live in the U.S., Australia, France, Germany, Italy, and the U.K.. These studies show that the average protein intake of vegans is 13% of the calorie intake.[3] This meets or exceeds the recommended intakes for protein.

What sorts of vegan or raw diets may be deficient in protein?

Three categories of plant-based diets provide insufficient protein. These are diets in which most of the calories come from fruits, diets centered on vegan junk foods, and diets that are extremely low in calories. Let’s explore each of these:

  1. Fruitarian Diets

    Only 2% to 10% of the calories in fruits come from protein. So for example, fruitarian diets in which 75% of the calories come from fruits, can be low in protein. A study conducted in Germany on 43 people who consumed raw vegan diets showed their diets to provide, on average, only 8.2% of their calories from protein.

    Their calorie intakes were also somewhat low; the men and women on these raw vegan diets averaged caloric intakes of 1,888 calories per day. Many of the women’s intakes of calories, protein and other nutrients were low, and one in four women of childbearing age had amenorrhea (absence of menstrual periods).[4], [5], [6]

  2. Extremely Low-Calorie Diets

    A study of vegan women in Vietnam showed intakes of 1,130 calories and 34 grams of protein per day. Weight loss diets also can be low in protein. It is a challenge to design diets that provide adequate protein (and other nutrients) unless the caloric intake is at least 1500 calories per day.[6]

  3. Junk-Food Diets

    The “junk-food diet” is not the most common among vegans and vegetarians, but it’s possible. Not enough legumes and whole plant foods are consumed to meet recommended intakes for protein and other nutrients.

    A “junk food” diet might contain enough calories. But too many of these calories come from the sugars and oils in processed foods and flour products.

    Refined grains aren’t that much lower in protein than whole grains. But many of the calories in cereals, croissants, muffins, and other flour products come from sugars and oils.

How can I determine if I’m getting and absorbing enough protein for my age and gender?

The amounts shown at the beginning of this lesson (0.9 g protein per kg body weight) are suitable for adults of both genders. Of course, if you are a man, you may be larger than most women, and thereby your recommended protein intake will be higher.

Although a senior’s RDA for protein doesn’t differ from that of a younger adult, many experts suggest a daily protein intake of at least 1 or 1.1 g/kg/day for those over age 65.

How would I know if I was not getting enough?

Protein is required for maintenance of every cell in the body. So deficiency symptoms are numerous and could easily be confused with deficiencies of other nutrients. If you were eating or absorbing too little protein, you might have dry skin or hair that fell out easily. Over months of insufficient protein, your body would also lose muscle. And over years, your bones could be affected.

Kwashiorkor is the specific name for protein deficiency. This condition is rare in Americans, though some elderly people are at risk for it. If you had kwashiorkor, you could exhibit such symptoms as diarrhea, fatigue, hair and skin color changes, loss of muscle mass, reduced immunity, lethargy, rashes, swelling or a protruding stomach.

What blood test can I get to find out if I’m eating enough protein?

The Serum albumin blood test indicates whether or not you have a protein deficiency or severe malabsorption. The test also shows some other malnutrition indicators.

References

  1. [1] National Research Council. Dietary Carbohydrates, Starches and Sugars. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Washington, DC: National Academies Press; 2005.

  2. [2] World Health Organization/Food and Agriculture Organization/United Nations University. Expert Consultation. Protein and amino acid requirements in human nutrition. WHO Technical Report Series – 935. (World Health Organization/Food and Agriculture Organization). 2007.

  3. [3] Mangels AR, Messina V, Messina M. The Dietitians Guide to Vegetarian Diets. Jones and Bartlett Learning Ltd. 2011.

  4. [4] Davis B, Melina V. Becoming Raw. Book Publishing Co. 2010.

  5. [5] Koebnick C et al. Long-term consumption of a raw food diet is associated with favorable serum LDL cholesterol and triglycerides but also with elevated plasma homocysteine and low serum HDL cholesterol in humans. J Nutr. 2005;135:2372-8.

  6. [6] Davis B, Melina V. Becoming Vegan: Comprehensive Edition (2014) OR Express Edition (2013) Book Publishing Co.

12 Comments

  • ochoaregina@yahoo.com

    06/30/2016

    Thank you for this wonderful information. It is good to know one can take a “Serum Albumin Blood Test” and check if one has a protein deficiency or protein malabsorption. It is also nice to know the 3 categories of vegan people who do not take enough protein: a) the ones that eat mainly fruit, b) the ones that eat trash food and c) the ones who limit their caloric intake. Thank you again!

  • I’m confused about cooking versus not cooking. In one lesson (and much literature I’ve come across) we’ve learned that cooking depletes a food of nutrients.

    Yet when it comes to protein, cooked spinach is shown to have more protein than raw spinach. How does it increase beneficial protein and at the same time “devitalized” it due to cooking?

    • Catrina Mcfate

      09/03/2014

      A cup of cooked spinach has more protein than a cup of raw spinach mainly just because it shrinks the spinach by reducing fiber and compacting the spinach. If you compare cooked lentils to raw lentils on the other hand, a raw cup has more protein.

      Cooking is chemistry. When we cook a food its chemical composition changes. Certain things more easy to absorb and utilize while others become unavailable biologically for humans. Tomatoes are a great example. Lycopene content is actually increased by the cooking of tomatoes. Vitamin C gets depleted when the tomato is cooked.

  • Alan Slezewick

    08/20/2014

    You can get enough protein as a vegan. Yet I do think one can get deficient. With all the food allergies, digestive issues and processed foods around… I still can’t eat beans often. I am using high quality protein powders to help build my body.

  • Rebecca Legun

    01/15/2014

    Very informative lesson and I do get challenged on the protein issue so this information will help. Thank you!

  • Juliette Pierre

    11/13/2013

    Dear Mr. Justice I just want to say thank you and your team for debunking some myths on protein. As a vegan I’m continously faced with arguments like, I can never get enough protein and especially B12 from strictly plant sources; that I would have to revert to a meat based diet to get this nutrition. I’m now exploring my Lessons since my computer crashed.
    So, keep up the splendid work you guys in informing us of all these health benefits.
    Juliette

  • Marilyn Seay

    11/11/2012

    I just got a green star juicer and make and drink a lot of vegetable fruit juice combined. Does removing the fiber from food reduce the protein content in any way? Since it is possible to drink more plants in juice form than I could eat in solid form, perhaps I am getting more protein per serving. Let me know and thank you, Marilyn

    • I don’t believe that juicing reduces amino acid content. But it is worth doing your own research into it, Marilyn.

      The main thing removed with juicing is fiber. Fiber itself does not contain carbs, protein or fat.

  • Piper Perreault

    07/04/2012

    So theoretically one doesn’t need that much protein in their diet, but in reality many people need more than the charts and vegetarian logic would have you believe.

    • Sasha Luci

      07/07/2012

      I think a very important thing to remember is that we are not made from cookie cutters, not everything will work out exactly the same for any of us. LISTEN TO YOUR BODY.
      I know when I need more protein and i am very thankful to to know how to take care of that with a plant based diet.

  • Piper Perreault

    07/04/2012

    I’ve had serious protein deficiencies a few times over the past decade, which I didn’t realize because I wanted to believe that it was a myth that I needed more protein. But then I lost a lot of hair, etc.

    Yes there’s protein in vegan sources, but you need to eat more protein if your body isn’t absorbing it well because of allergies and other digestive issues which are very common.

    You are not what you eat, but rather what you absorb.

  • Laura Honig

    06/28/2012

    Your tables are very thorough and the facts speak for themselves. I think the obsession with protein is not based on information like this, but more about how how people feel after eating meat/high-fat foods. A feeling of satiety and comfort is what they fear they will be lacking if they go vegetarian or vegan or raw. But classes like this and preparing food carefully and lovingly can help move people gently over to less meat.

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