Most Americans get enough protein through their diets to meet their daily needs. The average healthy adult needs about 50 g of protein a day, but some -- endurance athletes, weight-loss surgery patients, cancer patients and the elderly -- may need more, according to the Centers for Disease Control and Prevention. Protein shakes can help in these situations but should not be the sole source of nutrition on a long-term basis.
Our bodies produce some amino acids, the building blocks of protein, but nine essential amino acids must come from dietary sources. Complete proteins such as eggs, meat, fish, poultry, dairy products and soy provide all nine essential amino acids. Incomplete proteins such as rice, beans and dried peas provide an insufficient amount of at least one essential amino acid. Certain combinations of incomplete proteins such as beans and rice provide all of the essential amino acids when eaten during the same day.
Protein shakes come in ready-to-drink containers as well as in powdered form intended for mixing with your choice of a liquid. Because the U.S. Food and Drug Administration does not regulate supplements, the nutritional content of these products varies widely. When choosing a protein shake, check the nutrition label for information about calories, fat, sugar and protein per serving. A healthy shake for someone looking for more protein without adding too many calories would contain at least 15 g of protein and no more than 5 g each of fat and sugar per serving, according to Highland Hospital.
Using Protein Shakes
Protein shakes purchased without a prescription are intended to serve as snacks or to replace one or two meals a day. If you add them to a balanced diet, you risk taking in too many calories, which can cause you to gain weight. Eating too much protein over long periods may cause damage to your kidneys or liver because they must work harder to process the waste products. If you need extra protein for medical reasons, follow your health care provider's instructions carefully to avoid taking in too many calories or too much protein.
Protein Shakes as a Sole Source of Food
Nonprescription protein shakes are not meant to be a long-term, total nutrition solution. Even the highest quality shakes do not provide sufficient fiber and micronutrients to meet the needs of healthy, active individuals. Morbidly obese individuals who need to lose large amounts of weight may benefit from very low-calorie diets that may include only specially manufactured shakes under medical supervision, according to the Weight-control Information Network. You should not, however, attempt to replicate such a diet at home without medical supervision.