First up, the *beef* on protein (because I just can't resist bad wordplay!)
Protein comes from animal sources such as meat, dairy, and eggs and from plant sources such as beans, nuts, seeds, and even some grains. It is possible to consume enough protein for good health on a vegetarian or vegan diet if you plan your food choices well.
Protein is an essential nutrient meaning that we must get it from our food. Proteins break down in our bodies to amino acids. Our bodies cannot make all the amino acids it needs to function and approximately 25% of amino acids are lost to other uses every day, which is why protein is an important part of the daily diet.
Protein has many functions including:
· Provides body structure by building and maintaining muscle, bone, and other body tissue
· Allows for movement (40% of body protein is muscle tissue)
· Regulates gene expression
· Integral part of enzymes, hormones, and neurotransmitters
· Immunity through antibodies
· Transports of vitamins, minerals, oxygen and other substances through the body
· Regulates fluid and electrolyte balance
· Maintains acid-base balance
· Necessary for blood clotting
· Used as fuel when other sources of energy are not available – this is not an efficient use of protein!
· Protein is satiating – it helps us to feel full and satisfied
For a generally healthy adult, the range for protein intake is set between 10% and 35% of daily calories. A person consuming a 2,000 calorie diet would have a range of 200 – 700 calories. Since 1 gram of protein has 4 calories, this is a range of 50- 175 grams of protein per day.
The DRI recommendation for generally healthy adults is 0.8 grams per kilogram of body weight. To convert pounds to kilograms, divide weight by 2.2. For example, a 150 pound person is (150 divided by 2.2) 68.18 kilograms. This person would consume around 54 grams of protein per day, which is the low end of the above range.
People with specific health conditions or concerns may need a different amount of protein in their daily diet. Many Americans, however, over-consume protein in the belief that it will help them build muscle more efficiently. Any protein over what the body requires is converted to fat. A high protein diet can also overwork the kidneys.
Reference: Nutrition Concepts and Controveries, 12th ed. by Sizer and Whitney, 2012. ISBN-13: 978-1-1133-62818-7.