What is protein made of?
Protein is made up of carbon, hydrogen, and oxygen (as are the other macronutrients) and one more element non of the other nutrients have–nitrogen. If you have hear someobyd talking about being in positive nitrogen balance or negative nitrogen balance what they are referring to is whether they are in an anabolic state–able to build muscle–or in a catabolic one–losing muscle. Some foods contain what is called complete protein–that is, they provide all the amino acids necessary to produce usable protein. Examples of these foods are milk, eggs, meat, fish and various vegetable products, such as sybeans. But even these foods contain differring amounts of usable protein per weight. That is, even though a food might contain, say, 10 grams of protein your body is able to use only certain percentage of it–for example, only 7 or 8.5 grams.
