7 Popular Protein Myths Totally Busted by Science
Think you know everything about this powerhouse macronutrient? Don't be so sure. Here's the truth behind common myths about protein.
Overview
Talk to a handful of people about protein and chances are you'll hear conflicting information that can leave you with a lot of questions. How much protein should you be eating? What are the best sources of protein? Is too much protein bad for you? But it doesn't need to be so complicated.
But first, what is protein? It's a molecule made up of amino acids. It's also one of three macronutrients (along with carbohydrates and fats) that you need to consume each day. Protein is required for the structure, function and regulation of the body's tissues and organs. Read on to learn the truth behind common myths about protein.
MYTH 1: All Protein Sources Are the Same
The truth? Not all sources of protein are the same. There are 20 amino acids — some essential, some nonessential. Our bodies produce the 11 nonessential amino acids, so it doesn't matter if we also get those from our diets or not. However, our bodies can't make the nine essential amino acids, so we need to get them from our diet.
Protein sources that contain all nine essential amino acids are considered "complete" proteins. These include meat, fish, dairy, eggs, soy, quinoa and hemp. Other "incomplete" proteins aren't devoid of nutrition; they simply don't provide all the amino acids you need. "If you eat a variety of incomplete proteins during the day, you should get all the amino acids that you need," says Mike Roussell, Ph.D., author of "The MetaShred Diet."
Read more: 8 Unconventional Protein Sources and Tips to Add More Protein to Your Diet
MYTH 2: High-Protein Diets Wreck Your Kidneys
One role of our kidneys is to filter the byproducts of protein metabolism and breakdown. But eating more protein won't damage your kidneys if you're healthy. In a 2018 study published in the journal Nutrients, 310 prediabetic men and women followed a specific plan to lose weight for a year. Researchers found that intakes of more than 1.6 grams of protein per kilogram of body weight a day (about double the recommended daily intake) was not associated with decreased kidney function.
And a 2000 study from the International Journal of Sports Nutrition and Exercise Metabolism found that consuming up to 2.8 grams of protein per kilogram of body weight daily (nearly four times the RDI of protein) caused no impairment of renal function. However, one very important exception to this is if you have kidney disease. Talk to your doctor about your protein consumption, as a high-protein diet may worsen your condition.
MYTH 3: Too Much Protein Will Give You Osteoporosis
There may be a tiny grain of truth to this myth, but it's also misleading. According to a 2011 Swiss study, eating more than two grams of protein per kilogram of body weight and also less than 600 milligrams of calcium daily may be detrimental for bone mass and strength. For a 150-pound (68-kilogram) person, that means consuming more than 136 grams of protein (about three chicken breasts) but less than 600 milligrams of calcium.
But if you watch your calcium intake, protein is actually good for bone health. "Not eating enough protein is a bigger problem with risk of osteoporosis, as inadequate protein intake has been shown in several population-based studies to be associated with decreased bone health," says nutritionist Dr. Mike Roussell. Researchers believe protein may benefit our skeletons by boosting calcium absorption, stimulating the secretion of insulin-like growth factor 1 and enhancing the growth of lean body mass.
MYTH 4: Your Body Can’t Handle More Than 30 Grams of Protein a Meal
This myth comes from the fact that your body needs 30 grams of protein in order to maximally stimulate muscle protein synthesis (the repairing of damaged proteins and building of new proteins). And while 30 grams per meal is optimal, according to Dr. Roussell, more doesn't lead to additional benefits.
In a small study published in the Journal of the American Dietetic Association, researchers gave 17 healthy adults and 17 healthy elders either a four- or 12-ounce serving of beef. Then they took blood samples and thigh muscle biopsies to assess the subjects' post-meal protein synthesis. In both age groups, the 12-ounce serving (about 90 grams of protein) caused the same increase in muscle protein synthesis as the four-ounce (30 grams) serving. It's not that your body can't handle extra protein — it just doesn't need it.
MYTH 5: There’s No Such Thing as Too Much Protein
Although many experts agree that we should be eating more than the recommended daily protein intake of 0.8 grams per kilogram of body weight (0.36 grams per pound), you don't want to go too far. "There is no good reason to eat more than 30 to 35 percent of your calories from protein," nutritionist Mike Roussell says. (That's more than one gram of protein per kilogram of body weight.)
"Beyond that, you can give your body better sources of energy in the form of fat or carbs." Plus, eating too much of any one macronutrient can lead to nutritional deficiencies, as you'll have to cut back on other foods, such as vegetables, fruit, whole grains and healthy fats. This may cause you to fall short on fiber, essential fatty acids, vitamins, minerals or other nutrients necessary for your body to function at its best.
Read more: How Much Protein Is Right for You?
MYTH 6: You Need a Protein Shake Right After a Workout
Previous studies suggested the presence of an "anabolic window" — a magical time of somewhere between 30 minutes and an hour after a workout during which you had to down protein or else you'd miss out on muscle-building benefits. However, we now know that this window is much larger.
A 2013 review suggests the window is four to six hours. Still, it's best to eat a meal with 30 grams of protein within two hours of finishing your workout, nutritionist Mike Roussell says. "After you exercise, your body benefits from having protein. It doesn't need to be immediate, but best practice would be within two hours and then regularly at each of your meals after that."
Read more: 8 Things to Consider When Choosing a Protein Powder and Our 5 Top Picks
MYTH 7: Avocado, Chia Seeds and Hummus Are Packed With Protein
Don't believe a recipe or food is a great source of protein unless you read the nutrition facts. An entire medium avocado has a mere four grams of protein. Chia seeds have about three grams per tablespoon, so that teaspoon in your smoothie isn't going to do much for you. Ditto for hemp seeds, which have about the same amount of protein.
And you'd have to eat more than an entire 10-ounce tub of most hummus in order to consume as much protein as in a grilled three-ounce chicken breast. It's not that these foods are bad — after all, you eat more than one food at any meal to tally up to 30 grams. But educate yourself or see a registered dietitian if you aren't sure how to get the protein you need.
What Do YOU Think?
Have you heard of any of these protein myths before? Did you know the science behind them? Which of these were surprising to you? Have you heard any other misinformation about protein? Share your thoughts and suggestions in the comments below!