Protein in a vegan diet

There seem to be two kinds of people in the world: people who think vegans can never ever get enough protein from plant foods alone, and people who think protein is never a problem and people should stop nagging vegans about it.

First things first: it is true that it is very easy to get all the protein you need on a vegan diet. All natural foods contain some protein. That does not mean that it is impossible to get protein deficient on a vegan diet. Extracted oils contain no protein at all. Some fruits and fruit juices contain practically no protein. Sugar, of course, contains no protein. Some nuts and grains do not contain much protein. So, if you are eating a substantial amount of these products, you must make sure to eat protein rich foods as well to compensate. Also: if you are on a very low calorie diet, you risk not getting enough protein.

Why do you need protein?

Protein is necessary for growth, maintenance, and repair of all body cells (muscles, hair, nails, red blood cells). From Harvard's page about protein: Lack of protein can cause growth failure, loss of muscle mass, decreased immunity, weakening of the heart and respiratory system, and death. Protein is necessary for maintaining muscles, and muscles are necessary for antibodies to fight disease. Recent research also suggests that a moderately high protein diet prevents osteoporosis. Hair loss and being sick often may be a sign of protein deficiency.

How much protein do you need?

There are many different opinions and complicated formulas about this. Most experts today agree that you should get about 1 gram protein per kilogram (2.2 pounds) of bodyweight. For a 60 kg (130 pounds) woman that means 60 grams of protein a day. Since one gram of protein is four calories, this means that 240 calories of your diet should come from protein. This is about 13% of an 1800 calorie diet.

What about food combining?

It is commonly believed that plant protein is of lesser quality than animal protein. It is true that we require a little more protein from plant foods than from animal foods, but if you eat the recommended one gram per kilogram, you likely get enough protein. Some plant foods do not contain substantial amounts of some amino acids (the building blocks of protein), but that's not unique to plant foods. Beef, for example, contains less methionine/cysteine. Spinach, on the other hand, has a better protein profile than milk. Dr. Harris has a great (somewhat technical) article explaining why you should not worry about amounts of amino acids at all if you eat a varied diet. (He recommends 0.9 gram protein per kilogram bodyweight, which I think is a little low, but the information is still valuable.)

Recommendation

I recommend to track your food intake for a couple of days in a nutritional analysis program such as FitDay. If you notice your protein intake is low, increase your intake of green vegetables and beans and limit foods with no protein such as oils and sugars. If you are eating rice, choosing a higher protein grain such as oats is also helpful.

Protein contents of plant foods

This is just for the number geeks among you: a list of protein content of various plant foods per 100 grams (3.5 oz). Click on a column heading to sort by that column.

June 21, 2006