You know protein is good for you, especially if you’re trying to build muscle. You’ve seen the powders, the shakes, and the power bars. But what is the importance of protein in your diet? What exactly does it do? How much of it do you need every day? And can it help you lose weight, too?
Protein is one of three macronutrients essential for life, the other two being carbohydrates and fat. Of the three macronutrients, protein is probably the least understood, and possibly the most complex.
What is the importance of protein in your diet and what does it do?
Protein is the main component of most of your cells. It’s also a major component of your hair, nails, skin, muscles and soft tissue. The main function is to build, replace and maintain these structures. Protein can also act as a source of energy, although your body will only use protein as an energy source if it doesn’t get all of the calories it needs. Like other calorie sources, if you eat too much protein, your body will store the excess as fat.
What is protein?
Proteins are made up of complicated amino acid chains. There are 20 amino acids in total, but 9 of them, called “essential amino acids,” must come from your diet. Your body takes amino acids (which are basically like building blocks) that it has broken down from other chains, and rebuilds them into new chains, each of which serves a specific purpose.
Sources of protein
Sources of protein include meat; poultry; fish (one of the best sources); milk and milk products; eggs; beans; nuts; and seeds. Some surprising sources include rice and corn. Some proteins, such as those derived from animals, contain all 20 amino acids, and are considered to be “complete” or “high-quality” proteins. Other proteins -- such as those found in rice, corn and beans -- are lacking in some amino acids, and are considered to be incomplete proteins. Eating two or more incomplete proteins in the same day can ensure you get all of the amino acids you need.
So, how much do you need?
The CDC recommends that men from 19 to 70 years old get 56 grams of protein daily. To put this in perspective, one 3-ounce piece of meat contains around 21 grams of protein, and one cup of dry beans has about 16. However, some doctors believe that men actually need more than this amount – sometimes far more. Hard-core athletes may need as many as 180 daily grams of protein, according to Mark Tarnopolsky, M.D., Ph.D., who studies exercise and nutrition at McMaster University. Men who work out regularly or are actively trying to build muscle may need as many as 80 grams per day.
Protein and Weight Loss
There is evidence that it can help with weight loss. In a 2005 study by the American Journal of Clinical Nutrition, commented on their study that the participants who had an increase from 15% to 30% if their total caloric intake and reduced their fat intake from 35% to 20% of their total calories experienced sustained and lasting weight loss.