Protein: Just the Facts
Protein is all the rage in the health and fitness industry. Protein is portrayed as a “magic bullet” and the answer to many diet and exercise questions. I used to believe that protein was needed before a workout to provide energy. I also believed that protein should be consumed in greater quantities than any other nutrient. Unfortunately, I was wrong on both counts. The more I have learned about nutrition the more I realized how much misinformation is out there, how people can fall for almost anything-and I was no exception. There are countless myths surrounding the purpose of food groups, vitamins, and minerals. Today we will breakdown the truth about protein. Instead of addressing the countless claims that protein is not, let’s look at the facts about protein.
- Macronutrient. Protein is 1 of 3 macronutrients, the other 2 being carbohydrate and fat. A macronutrient is simply a nutrient that our bodies need in large quantities. All food can be classified as a carbohydrate, fat or protein or in many cases a combination.
- Metabolism. The breakdown of protein is a complex process. In its simplest form, protein is degraded to amino acids and used by the liver to make new proteins, glucose, used as energy if carbohydrates are insufficient, or stored as fat. Excess protein is not stored in the body or used to continue building muscle. Therefore, high protein diets in hopes of building muscle are somewhat futile. All excess calories, no matter the source, will be stored as fat in the body.
- Function. Protein is made up of amino acids which are the building blocks for muscle. The main functions include structural and mechanical support, maintenance of body tissue, acid-base balance, building enzymes and hormones, and immune response. Protein is used for energy when insufficient amounts of carbohydrate and fat are available. Consuming enough carbohydrates and fats allows protein to be used for its primary function.
- Satiety. One noteworthy function of protein for those looking to manage their weight is satiety, the feeling of fullness. We already discussed that excess protein is not stored as muscle. Protein in and of itself does not cause weight loss. However, consuming enough protein in balance with carbohydrates and fats can help keep you feeling fuller longer. This in turn can contribute to fewer consumed calories.
- Daily Needs. Fifteen to 20% of the diet should come from protein. On average, adults require .8g/kg/day for maintenance. You can calculate your own needs by taking your weight in pounds, dividing by 2.2, and multiplying by 0.8. For example, a 150 lb person (150lbs/2.2kg x .8g) needs 55 g of protein each day just to maintain proper function. Daily requirements for athletes may be as high 2g/kg/day.
- Food Sources. While there is a small amount of protein found in many vegetables, the primary sources of protein are from animal products such as meat, poultry, cheese, eggs, and yogurt. Protein is also found in peanut butter, beans, nuts, and soy.
- Quality. The quality of protein is determined by one, how easily it can be digested and two, the types and amount of amino acids the food contains. “Complete” proteins have all 9 essential amino acids and some of the 11 nonessential amino acids. Animal protein is considered complete. “Incomplete” proteins are low in 1 or more of the essential amino acids, and plant protein is one example. While animal proteins are typically of higher quality, vegetarians can still meet their daily needs for protein requirements with a little planning.
- Supplements. A person consuming a typical American diet is most likely exceeding their daily protein requirements. Even most athletes can meet their protein needs through whole foods. On average, 1 scoop of whey protein powder contains 25 g of protein. Remember the needs of a 150lb person? Two scoops of protein powder would almost meet the daily requirement. And this does not even take into consideration the amount one consumes from his or her diet! For the average person, supplements are not recommended.
If I could summarize the purpose of protein in just a few sentences it would be to say this: protein is a vital macronutrient which has numerous roles in the body. When comparing carbohydrates, fats, and protein, protein should be consumed in the smallest amount. Consuming a high protein diet in hopes of building excess muscle and achieving weight loss is futile. However, protein is an essential nutrient that we cannot live without.