Complete and incomplete proteins

I have been wondering about this subject for a long time, so I am excited to research and write on it. I know that beans contain protein, but that they need other foods, such as rice, to form a complete protein. Why do we need complete proteins? How much do we need? What grains other than rice can I pair beans with?

What is protein and why do we need it?

Protein is made up of different types of amino acids. Our body can manufacture some amino acids; the rest we need to get from food. We need them all: our body uses these amino acids as the building blocks for its structures, from muscles to hair to blood cells.

What are complete and incomplete proteins?

A complete protein is a food that contains all 9 of the essential amino acids that our body cannot produce. An incomplete protein is a food that contains some, but not all, of these essential amino acids.

Animal products contain complete proteins: meat, fish, milk, and eggs. Soy and quinoa also contain complete proteins.

Other vegetable sources of food such as beans and grains contain incomplete proteins. But making complete proteins from vegetable sources is easy: the rule of thumb is bean plus grain. You don't even have to eat them both at one meal, as long as you eat them within a day or so of each other. Here is a great explanation of the different combinations you can make.

How much protein do I need?

I couldn't find a straight answer at the FDA website. However, they did say that getting enough protein is not a public health concern for Americans over the age of 4.

I couldn't really find a one-size-fits-all answer anywhere else, either. Everyone's protein needs are different, depending on their age, size, and other factors.

So I guess I'll just continue to stick to my rule that we try to eat some form of protein at each meal. Any advice on this?

Sources: How Much Protein Do You Need; What's a Complete Protein?; Complete and Incomplete Proteins in Grains and Vegetables.


  1. Wow! That is really great to know. I have wondered about this myself but have not gotten around to looking it up. Thanks for sharing!

  2. That is why beans and rice is so good for you!

    I have been planing at least two meals a week with beans, but I haven't been paying much attention to the grains, I will start that!

    BTW does bread count as a grain? Would beans with some whole wheat bread on the side count as a complete protien?

  3. That is very interesting. I know that for my gestational diabetes, the nutritionist told me to have protein with my carbs (usually grains or fruit) to stabilize or balance out the sugars, or something like that. If you have the carbs by themselves it spikes your blood sugar more. So I have been eating more protein than usual lately.

  4. I wonder if that statement is true of vegetarians as well? (the one about the average person getting enough protein)

  5. Bread should definitely count as a grain. It always works for us!

  6. What an interesting post, Mrs. Mordecai! Thank you for the information!

  7. This might help:

    Multiply your weight in pounds by .36 to .50 = Daily protein requirement (in grams)

  8. I learned what I know about protein from the More-with-less Cookbook. I used to balance it carefully, but in general, I think Americans eat rather richly, so I don't worry about it too much anymore. We only eat meat once or twice a week and not usually more than a deck-of-cards serving.

  9. I don't know whether or not my attempt to comment went through. If so, please disregard this one, if not, please consider the information in it.
    My understanding is that we do not need more protein to heal from illness or injury. As a matter of fact there is a fairly substantial body of research that water fasting, under appropriate supervision, is healing as your body is able to work at the problem and not consume its energy digesting food. At any rate, the only exception is if you have been burned. Burns require a great deal of protein in the diet to heal well.
    I don't remember where I got this information but I think my ex-husband who was a Dr. very interested in nutrition may have been my source. If anyone knows of another source that proves or not, I'd really appreciate knowing it. Thanks. Kol Toov (all good things), Marnie