When you think about protein, athletes and bodybuilders may come to mind, but there’s much more to it than increasing muscle mass. Protein plays an essential role in keeping your body healthy. So, how much protein do you need? And is there such a thing as too much?
From your hair to your toenails, protein is a primary component of every organ and system in your body. Proteins are also the body’s workhorses. They:
- help form new molecules
- give your body structure, with bone and tissue
- form hemoglobin, which helps carry oxygen from your lungs throughout your body
- send signals throughout the body that coordinate biological functions
- are key components of your immune system
When you eat more protein than you need for these functions, your body uses it for energy. Protein that isn’t used for energy becomes fat. Conversely, if you’re not consuming enough calories, protein is used to provide energy, instead of to maintain your body’s tissues.
You can’t talk about protein without knowing a little about amino acids. The proteins in your body are made up of 20 different amino acids. These amino acids are linked in various ways to create the different the kinds of proteins your body needs.
Ten of these are essential amino acids, which your body needs to function (although adults require only nine of these). They’re called “essential” because unlike nonessential amino acids, the body can’t produce them. They must come from protein you consume.
The amount of protein you need varies by age and gender. The Centers for Disease Control and Prevention (CDC) provides the following recommended dietary allowances (RDA).
|Age Groups||Grams of Protein Needed Each Day|
|Children, ages 1 to 3||13|
|Children, ages 4 to 8||19|
|Children, ages 9 to 13||34|
|Girls, ages 14 to 18||46|
|Boys, ages 14 to 18||52|
|Women, ages 19 to 70 and older||46|
|Men, ages 19 to 70 and older||56|
You may be surprised at how little protein you need. Most Americans consume far more than is recommended — on average, almost twice the recommended amount, according to one study.
For example, the RDA for protein will be met if you eat any of the following:
- 1 cup milk
- 1 egg
- ½ cup tuna
- ½ cup kidney beans
- 1.8 ounces of cheese (about the size of a man’s thumb)
Some sources of protein are healthier than others. When adding protein to your diet, keep an eye out for high levels of sodium, saturated fat, and cholesterol.
Too much protein in your diet can be a problem. For example, it may strain your kidneys. People who are most at risk of this are those who are in the early stages of kidney disease and don’t yet know they have it.
Too much protein — particularly animal-based protein — in your diet can also make you more susceptible to certain diseases. A recent study conducted at the University of Southern California found evidence that middle-aged people who consume too much animal-based protein were four times as likely to die of cancer. This is similar to the impact of smoking cigarettes.
Excess protein can also cause weight gain. Proteins normally give you a sense of fullness, which is desirable if you’re watching your weight. But you can gain weight when your consumption of protein outweighs your body’s ability to burn it.
Nutritionists categorize protein into three categories, depending on essential amino acid content: complete, incomplete, and complimentary.
- Complete proteins provide all of the essential amino acids. Some examples are meat, poultry, fish, dairy products, soy, or quinoa.
- Incomplete proteins don’t provide enough of one or more essential amino acids. Examples include peanut butter, whole grains, or vegetables.
- Complimentary proteins are two incomplete proteins that combine to provide all of the essential amino acids. Examples include rice with beans, rice with cheese, or sesame seeds on beans. Recently, it’s been demonstrated that you don’t need to eat complementary proteins together. Instead, you can enjoy them separately, within a 24-hour period.
Protein plays an important role in the maintenance and repair of your body tissue. The trick to balancing these functions is knowledge of how much protein your body needs each day. It’s also essential to choose plenty of healthful proteins that don’t add unnecessary fat or sodium. Does this mean you can’t ever have bacon again? Of course not, but practice moderation.