Source: NIH News in Health
The idea of eating more protein has gained popularity in the past few years. Some people may think the way to build body muscle is to eat high-protein diets and use protein powders, supplements and shakes. But there’s no solid scientific evidence that most Americans need more protein. Most of us already get all we need. Some of us may even be eating much more than we need.
Proteins play a key role in our bodies. They make up about 15% of the average person’s body weight. You probably know proteins as the major component of muscle. Muscles flex arms and legs, contract our hearts and create waves in the walls of our intestines to move food along. All this muscle activity accounts for most of the energy our bodies burn. The more muscle you have, the more calories you burn and the more food you need to maintain your weight.
Proteins also perform crucial activities within all the cells of your body. They move molecules from one place to another, build structures, break down toxins and do countless other maintenance jobs. Proteins play an important structural role in cells as well, making up a sort of miniature skeleton.
Proteins are actually chains of small molecules called amino acids. Some of these chains are constantly being broken down, and new ones are strung together to take their place. Your body can make some of these amino acid building blocks, but not all of them. The ones you can’t make are called essential amino acids.
Meat in general is a good source of protein, with a full mixture of all the essential amino acids . However, it can be high in fat. Try to select lean cuts such as top round and sirloin. Poultry, fish, eggs, nuts, seeds and legumes (dry beans or peas such as lentils, chickpeas and kidney beans) are also good sources of protein.
Most Americans already eat about 12-18% of their calories as protein. Dr. Van S. Hubbard, director of the NIH Division of Nutrition Research Coordination, says that most Americans don’t need to worry about getting enough protein. “Unless they have some other medical problem, most people are meeting or exceeding their protein requirements,” he says. “Since protein is such a common component of most foods that you eat, if you’re eating a relatively varied diet, you’re getting enough protein.”
Some people, such as vegetarians, do have to pay attention to the protein in their diets. While animal proteins have all the essential amino acids, plant-based proteins can have low amounts of some. That’s why vegetarians have to eat protein from several different sources to get all the different amino acids they need. As Dr. Hubbard explains, “If you don’t eat enough of certain amino acids, it doesn’t matter if you have more of others.”