What Is Protein?
After water, protein is the largest component of the body. For every 2 pounds of body weight, about 1 gram of protein is required every day. If a person does not get enough protein, the body may break down its own tissue to function.
Protein comes from both animal and plant sources. Animal sources include meat, poultry, eggs, and dairy products. Plant sources include nuts, seeds, and beans. Some fruits and vegetables (e.g., broccoli, cauliflower, coconuts, dates) contain small amounts of protein as well.
When choosing a protein source, it is important to be aware of how much fat comes along with the protein. For example, ground beef comes in several different varieties: regular, lean, and extra lean. The differences in fat content among these three choices are significant. Regular ground beef can have as much as 30 percent more fat than extra lean.
The different forms of protein in food sources are made up of amino acids, which are like building blocks. There are 20 different types of amino acids. About half can be produced by the body; however, the other amino acids cannot be made by the body, so they must come from food. Amino acids that the body cannot produce are called essential amino acids.
Protein food sources that contain all 20 (essential and non-essential) amino acids are called complete proteins. Food sources that lack one or more of the 20 amino acids are called incomplete proteins.
Protein that comes from animals and soy products are complete proteins. Most plant sources lack one or two amino acids and must be combined in the diet to form complete sources. For example, brown rice and beans eaten together are a complete protein source, but alone they are each incomplete.
According to our sister publication Remedy's Healthy Living Spring 2013, getting a healthy dose of protein doesn't necessarily mean splurging on fancy fish and pricey cuts of meat. Try planning some of your meals around beans, eggs, boneless chicken thighs and canned salmon instead. All are great protein sources that don't pack as hefty a price-punch.
High-protein diets, which should be followed only under the direction of a qualified health care provider, licensed dietician, or nutritionist, require extra calcium, as the process of digesting protein requires calcium.