Most protein powders are made from soy, egg, rice, or casein or whey (both milk proteins), often with added nutrients to support the diet or fitness goals of people using them. Blended into shakes, sometimes with added fruit and fiber, they are sometimes used as meal replacements during a weight-loss program.
Protein powders are available in canisters in plain and flavored varieties—the plain varieties are bland and nearly tasteless, making them easy to incorporate into foods.
Natural varieties with no artificial ingredients are also available.