What's Protein Do for You? Is Too Much Bad?

You’ve heard buzz about all kinds of diets. One you may have heard about is a high-protein diet, which has been popular among those who feel they want to build muscle. Many nutrition stores carry protein powders, supplements and shakes to support this type of diet.

However, the typical American diet already includes up to twice the amount of protein recommended by the World Health Organization.

But Is a High-Protein Diet Helpful?

Putting protein product marketing aside, the medical reality is that there’s no solid scientific evidence that the average American should eat more protein.

Most of us already get the protein we need in our regular diets. Those who do require more protein include pregnant and breastfeeding women, along with athletes (though specific protein needs vary based on the type of athlete and other variables).

What Do Proteins Do?

Proteins are essential for our bodies. They do a lot of important work in our cells. For example, proteins move molecules around in our bodies, build internal structures in our cells and break down toxins.

Proteins are chains of molecules called amino acids. These protein chains routinely break down and then new ones are built as replacements. The body can make some of your amino acid building blocks but not all of them. What we call the essential amino acids are the ones we can’t make. We can get those from food sources such as nuts, seeds, eggs, fish, poultry, lean meats and legumes such as dry beans or lentils.

Proteins Do Build Muscles

Different proteins make up about 15 percent of the average person’s body weight. Proteins are a major part of our muscles.

The 650 or so muscles we have account for most of the energy our bodies burn. As the amount of muscle we have increases through exercise, for example, the amount of calories we need to fuel those muscles increases. And the more calories you burn, the more food you need to eat to maintain your weight. However, most of us aren’t building the kind of muscle mass that warrants an increase in calorie intake, so whether you’re a body builder or not, take care with your diet. A good guide on the best diet for you can be found at ChooseMyPlate.gov.

Can Eating Too Much Protein Be Harmful?

Research has found potential links between high protein consumption and prostate cancer and diabetes. Studies have also found links between eating excessive amounts of protein and a higher incidence of kidney disease.

People who have kidney disease may find reducing their protein intake may slow unhealthy kidneys’ progress toward kidney failure.

Another possible issue with a high protein diet is that the foods (often red meat from animal sources) can be high in saturated fats, which have been linked to heart disease. The saturated fats can raise your cholesterol levels of LDL or “bad” cholesterol, which can interfere with blood flow in your body.

High levels of protein intake are also linked to calcium loss, which can impact bone health.

How Much Protein Is Enough?

The recommended daily allowance (RDA) is calculated by factoring a person’s age and weight. Adults should get about 10 percent to 35 percent of their daily calories from protein foods. That’s about 46 grams for women and 56 grams for men. Growing children and pregnant and lactating women need a little more.

As a sample reference for protein amounts:

  • 2 grams of protein are in ½ cup of broccoli
  • 6 grams in an egg.
  • 7 grams in 2 tablespoons of peanut butter
  • 8 grams in one cup of milk.
  • 12 grams in 1.5 ounces of chicken breast.
  • 11 grams in 8 ounces of yogurt.
  • 16 grams in a cup of chickpeas, cooked from dry.
  • About 21 grams in a 3-ounce serving of meat.
  • About 50 grams in an 8-ounce serving of meat.

To get more details about the right nutrition for you and your family, visit with a registered dietitian or your health care provider.

Meet the Author

Rachel Mau, MS, RD, CD, is a Clinical Dietitian at Aurora Sinai Medical Center in Milwaukee, WI.

Read more posts from this author

The information presented in this site is intended for general information and educational purposes. It is not intended to replace the advice of your own physician. Contact your physician if you believe you have a health problem.

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