Food protein is almost always preferable to generated proteins. Unprocessed and better for digestion, real food has sustained human life for millions of years, as it was designed for us. Protein powders are simply supplements to assist food in meeting the nutritional needs of bodybuilders - not the main option. Peruse real food sources for protein whenever possible.
Whey
Whey protein is most popular with bodybuilders and strength trainers for regular daytime use (meal replacements) as well as for the all-important post-workout meal. 50 grams (about two scoops of most brands) should be consumed about twenty minutes after completion of the workout, with 25 grams of dextrose. Whey can also be used in conjunction with meals. If you realize your chicken/rice dinner only provided 35 grams of protein, it might be a good idea to knock down a scoop of whey with a cup of water, to round the meal's total protein count to 60 grams.
Casein
Casein is made from milk sources and is a much slower burning type of protein. Many trainers advocate consuming casein before bed, as it will stay with the body for a longer duration than the faster-burning whey protein. Casein can also be taken in conjunction with whey for both a fast- and slow- protein absorption rates.
Soy
Soy isn't a great protein. It's used primarily by vegans or vegetarians who are struggling to meet their protein requirements without the use of meat (vegetarians) or any animal products whatsoever (vegans). Soy is made from plants and can be a good supplemental protein for bodybuilders due to its ability to help the body's digestive system.
