One final protein source that I eat often is fish. Cold water fish like salmon, mackerel, halibut, tuna and cod are not only excellent sources of protein, they are also a great source of Omega-3. So, fish not only provides plenty of protein, it gives you good fat as well!
Yes it is true that much of the meat and eggs produced today come from animals that are injected with large amounts of drugs. These include large amounts of growth enhancing substances and tons of antibiotics. While there is no current study to suggest any link between this and the growing unhealthy state of this country, I don’t need a study to tell me that this cannot be good for our long term health.
Whenever possible, I highly recommend buying and supporting naturally raised meat and egg producers. These are usually smaller beef and chicken producers who choose not to use drugs or antibiotics on their animals. In addition, many allow their animals to roam relatively free and have relatively normal lives as opposed to being cramped up in unnatural living conditions.
If you are a vegetarian, and cannot eat whey (which comes from dairy), eggs or fish, your only source of good quality protein is soy protein isolate. Soy protein isolate is a concentrated form of the protein that comes from soybeans. In amino acid content, soy protein isolate is comparable to most animal proteins. This is mainly due to the concentrate form of the supplement. This is not the case with other soy products like tofu.