How much protein do we really need?
“Do you get enough protein”? This is a question every vegan, and many vegetarians, hear so often that it has become the ultimate joke – it’s even a tee shirt. I have heard this question so many times. I used to say, “plants”, and list some of the plant protein sources like legumes, and then explain that even a banana has 1.3 grams of protein. Protein, what our bodies need, and our dietary sources of it, is a complex subject. This post is meant to give you some tools to help you answer these inevitable questions in a generally informed manner.
Plant Based Nutrition (or “what I did this winter”)
One of the best things I did this winter was to become certified in Plant Based Nutrition through eCornell . While I learned so many things, the course really changed my response to questions about protein. I now ask in return, “Do you know how much protein you need every day?”.
Having this knowledge allows me to have a much more thoughtful discussion, and it tends to diffuse the tension and defensiveness that vegans and non-vegans alike can fall into when the subject of protein comes up.
What is Protein For?
Protein is the only source of nitrogen in our diet except for some nucleic acids. Protein must be consumed to replace the amount of nitrogen that is excreted by the body during normal protein metabolism. The Estimated Average Requirement (formerly called the Minimum Daily Requirement) for replacing the proteins that are broken down and excreted as nitrogen end-products has been scientifically determined to be 0.5-0.6 grams of protein per kilogram of body weight per day. That’s it.
In order to accommodate deviations in the general population in terms of protein requirements, the RDA, or Recommended Dietary Allowance, is increased to 0.8 grams of protein per kilogram per day. The RDA is not the minimum. The RDA already has increased protein requirements built-in. This (already slightly increased) level represents about 8-10 percent of total diet calories. Think about it. If you were eating a 2000 cal/day diet, you would only need approximately 200 protein calories. A six ounce piece of cooked, boneless, skinless chicken breast has 222 calories from protein (277 calories total). Clearly, based on these numbers, for meat eaters its not just “get enough protein,” but that they are getting far in excess the amount of protein their bodies require. As a matter of fact, there are serious issues with excess protein!
You may even hear people talking about “essential amino acids”, “complete protein”, and “food combining”. Here it is really quick: protein is made of amino acids and there are nine amino acids that your body needs from food to fully synthesize protein (that banana mentioned above happens to have all nine, and more). The same amino acids found in animal “foods” are available in plants. Our bodies also have the amazing ability to utilize the amino acids provided by a whole food, plant-based diet, in order to synthesize new protein – making it easy to get enough protein (and more!). Food combining at a given meal, once considered to be essential for a “complete protein”, is unnecessary.
It’s Easy to Get Enough Protein
If an average woman weighs around 130lbs (59 kgs), she only needs about 48 grams of protein per day. A man weighing 170lbs (77 kgs) needs about 62 grams of protein.
That piece of chicken has 54 grams of protein!
Consider some great vegan protein sources:
- 1 cup green peas = 8 grams
- 1 cup of cooked oatmeal = 4 grams
- 1 cup of cooked lentils = 18 grams
- 1 cup of cooked broccoli =2.6 grams
- 1 cup of cooked brown rice = 5 grams
- 1 cup of cooked quinoa = 8.1 grams
It is easy to demonstrate with these examples that it is very easy to meet the body’s protein requirement with plant sources, all of which offer the additional benefits of being high in fiber and nutrients, things that everyone can agree on as essential to a healthy diet.
My hope is that you will also find this information helpful not only in terms of your own body’s protein requirements, but also inform and answer the questions of non-vegans who are considering a plant based diet but are concerned that they will not be able to get enough protein.
RDA for Protein: http://www.ncbi.nlm.nih.gov/books/NBK234922/#ddd0000067