Protein shakes are meal replacement products designed to deliver calories and high-quality protein in drinkable form. Protein shakes are popular among bodybuilders, some athletes as well as those attempting to lose weight because they are convenient, tasty and available in a range of calories as well as vitamin and mineral fortified. Protein source, content and caloric value varies greatly among these products.
Types
Protein shakes come in ready-to-drink form or as powdered shake mixes. Powdered shake mixes should be blended with water or milk per container instructions before ingesting. They are available in many flavors, and may be targeted toward a specific population or goal, such as low carbohydrate for individuals on a carbohydrate-restricted diet; weight gain or weight loss protein shakes; and shakes marketed specifically to men or women. Protein shakes may include extra ingredients, such as stimulants, herbal preparations and flavorings.
Average Nutrient Values
According to Women Fitness, protein shakes are designed to provide a maximal amount of nutrients in a form that is unlikely to promote body fat storage. Per serving, protein powder shake mixes usually provide 250 to 300 calories, 35 to 45 g of protein, 20 to 25 g of carbohydrates and 2 to 4 g of fat. They also are typically fortified and provide 50 to 100 percent of the Recommended Dietary Allowance, or RDA, for most major vitamins and minerals. Ready-to-drink protein shakes, on the other hand, may be lower in calories and protein, providing 15 to 30 g, and higher in carbohydrates and fats.
Protein Source
Protein shakes typically contain high-quality protein sources such as whey, soy and egg or casein protein. All of these are complete proteins, meaning, each provides all of the essential amino acids. There are benefits to each type of protein. For example, whey protein is considered to be the "gold standard" because it is particularly rich in branched chain amino acids (BCAAs). These amino acids are metabolized directly into the muscles after digestion and can be burned as fuel for energy or used to build new proteins. However, soy protein is richer in arginine and glutamine, two non-essential amino acids. Arginine promotes optimum blood flow, and glutamine is necessary for muscle cell volume and growth.
Benefits
Protein shakes may be beneficial for those who are short on time or who need a concentrated source of protein for athletic training, weight management or medical reasons. Although high-quality protein is readily available in many whole foods, such as eggs, chicken and dairy products, these foods may not be as readily available. Protein powder mixes and ready-to-drink shakes are portable and often can be thrown into a gym bag for later consumption. In addition to the protein, many shakes are rich in energizing carbohydrates and low in fat.
Warning
According to an article featured in the July 2010 issue of Consumer Reports, tests conducted by an outside laboratory on 15 protein drinks revealed that some pose serious health risks. All drinks tested contained at least one contaminant, such as arsenic, lead, mercury or cadmium. If consumed frequently, organ damage may result from heavy metal exposure. Furthermore, based on a review of government documents and interviews with fitness and health experts, Consumer Reports investigators concluded that most individuals consume more than enough protein from better, less expensive whole-food sources.
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