Natural or dietary proteins can be found in a host of food types. When thinking protein, most people think meat or animal-based products, for good reason: meat is an excellent source of complete proteins, although it also contains relatively high concentrations of fat and cholesterol. This is highly dependent on the type of meat; turkey breast has 17% protein content per weight, but is very low in fat while beef can contain up to 35% protein per weight, but just as much in fat. But meat is hardly the only source of protein available. Some vegetables, particularly legumes such as beans, chick peas, etcetera, contain high levels of proteins and almost no fat, making them favorites of vegetarians and vegans who may need to pay closer attention to their protein intake.
Unfortunately, vegetable proteins are not complete; they do not contain all nine essential amino acids necessary to good health. This is easily countered through protein combining, a practice in which several types of foods will be eaten together to ensure that all amino acids are presents; a good example of that are ubiquitous rice and bean dishes.
Natural protein and Whey protein have different uses, and under no circumstances should supplements, such as whey protein supplement, be used to completely replace dietary protein sources.
Dietary protein sources should meet everyone's - including athletes and bodybuilders - baseline protein needs. Protein obtained through food is highly bioavailable, and contains a host of vitamins, enzymes, dietary fiber and other nutrients absolutely essential to good health that will not be available in supplements, no matter how good. Except in very specific circumstances, no one besides athletes and bodybuilders should need protein supplementation.
Where whey protein supplements actually come into their own is to grow up lean muscle mass. Whey supplements assist bodybuilders and athletes saturate their skeletal muscle cells in order to permit them all the amino acids they require to grow throughout the recovery period after workouts, as well as during sleeping periods. To maximize saturation, experts recommend that protein supplements be taken as close as possible to the training period; opinions differ as to whether before or after is preferable. Whey protein supplements, commonly available as powder to be mixed with water, milk or juice, or in convenient low-carbohydrate bar form are ideal for this function, as they can be consumed at exactly the right time.