by Julie PoundsignWhey protein is extracted from milk and although only 20% of milk is whey, it is an effective supplement for weight loss and muscle gain. The rest of milks protein is called casein and in order to separate the two, the milk must be subjected to a series of purification processes.Whey protein, if its pure, will be free of most of the causes of milk allergies, as most of these are contained in the casein that is extracted during the purification process. Whey protein therefore ca