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.