Proteins are large molecules found in the cells of all living things. They make up our cells and tissues, maintain the structure and strength of our bones and muscles, and form the foundation of our blood, fingernails and hair. Our body uses protein to make many different specialized molecules, like hemoglobin, the part of red blood cells that carries oxygen to the rest of the body. Proteins also help build up the cardiac (heart) muscle! Although proteins can provide energy, they are not a primary source of energy for our bodies.
I think when people think of protein, their first thought is typically of meat. Without a doubt, meat is chalk full of protein, but there are other sources of protein too! Things like eggs, milk, cheese, fish, beans, nuts, pasta, breads, tofu, legumes and vegetables are also excellent sources of protein. There are two types of proteins, and each type comes from different food sources.
Complete (High Quality) Proteins
- These proteins are highly digestible (you can digest about 90% of complete proteins)
- Mostly found in animal sources like meat, poultry, fish, and dairy products
- Also found in two vegetable sources: quinoa and soybeans
Incomplete (Low Quality) Proteins
- Found primarily in vegetable sources, like grains, legumes and vegetables
- Proteins in grains and vegetables are about 60-90% digestible
- Proteins in legumes are 80% digestible
How much protein should I be getting a day?
The recommended level of protein intake for adults is 0.8 grams per kg of body weight (*1kg = 2.2lbs). For example, a 130lb woman would need approximately 47g of protein a day and a 170lb man would need approximately 62g of protein a day. In order to meet or maximize your nutrient requirements, it is recommended you get a good variety of protein from different sources every day.
*As a little side note, vegans need a wide variety of incomplete proteins to compensate for the lack of meat in their diet from complete proteins!