Egg protein is a super bio-available protein second only to whey. It is a released more slowly than whey, which makes it perfect for use throughout the day. You may want to mix some egg and whey proteins for the most bio-available protein shake in the planet!
As far as uses go, eggs may be even better than milk protein. You can eat fried eggs in the morning with breakfast, eat hardboiled eggs throughout the day (like fruit, all you do is peel them and eat them) and its liquid in a raw form so you can mix it in plenty of things.
Being rich on protein, yolks have a very taxing effect on your liver. So out of precaution, limit your egg yolks to three a day and take a couple of weeks break once in a while. But eggs should make up at least a percentage of your weekly protein intake.
It is a perfect blend of casein and whey that may yield great results and because of its convenience should make up a large portion of your protein intake. The combination of casein and whey has been found to be the best protein source in meals. This is why almost all MRP's use the blend as the base for their mix of protein.
Though chicken seems to hold some kind of god-like status in bodybuilding circles, it's actually red meat that yields better results. Several studies have shown that people consuming red meat gained more mass than those consuming the two favorites in the sport: chicken and tuna. That doesn't mean you need to dismiss the other two. Both sources are prime nutrition when dieting. Tuna and the white part of chicken are low-fat and high-protein. Plus they are more easily transformed into tasty snacks you can carry around anywhere. But that big juicy steak will still give you better gains.
Casein is the other protein that is isolated from milk. Casein is the perfect complement to whey. A property of micellar casein is that it has the ability to provide a steady release of amino acids into the blood stream, which makes it an excellent choice for a long lasting anti-catabolic (muscle protecting) protein.
Whey protein is more readily used as an alternate source of energy (that's the reason you have to use enough carbs when supplementing with whey for bulking). The less chance you have of a protein being used as energy, the more carbs you use as energy. The more carbs you use, the less carbs stored as fat. So casein may prevent you getting fat too fast...
Soy has been shown to exhibit positive health benefits for both men and women. Studies have shown they may reduce the risk of hormone-dependent cancers (breast, prostate, etc), and other cancers as well. Soy's primary health benefits include reducing high cholesterol and easing the symptoms of menopause (due to the fact that it contains estrogen like substances called phyto-estrogens). Soy has also been shown to help with osteoporosis by building up bone mass. Because of this, 1 serving of soy protein per day is recommended for women for its health benefits.
Soy alone is practically useless with its BV value being a distant 49. But as an addition to an already rich protein spectrum it may serve a thousand uses. Its main use is protecting the cardiovascular system by lowering LDL (low-density lipoprotein) cholesterol. Bad cholesterol is one of the leading causes in arterial diseases. Bodybuilders should be aware of this, because meat, and especially that all-important red meat, could increase LDL cholesterol.
Everyone read that a high amount of soy in your diet may lead to breast cancer, brain damage and infertility in boys. The result of a high amount of flavonoids within the protein strands that may mimic the actions of strong estrogens. Then again other compounds are considered safe that exert similar effects. So don't worry about soy being bad, just don't go overboard and don't make soy your main source of protein. As with the other proteins it has its merits, but as with anything, moderation is the key.