The word “protein” gets thrown around a lot by those looking to lose weight, build muscle, cut back on (or increase their intake of) meat, and address general health concerns. But despite the ubiquity of the word, there’s a lot of popular misunderstanding of the role it plays in our diet.
INSIDER connected with Helen Mullen, registered dietitian and clinical nutrition supervisor at New York-Presbyterian Hospital to address some common misconceptions about protein from a dietary standpoint.
Myth #1: You can only get protein from animals
Anyone who’s ever been vegetarian or vegan has probably heard the phrase, “but where do you get your protein?” While animal products like meat and eggs are highly protein-dense, they’re far from the only kinds of foods that supply protein. Lots of plant-based foods not only provide a significant amount of protein, but they may be lower in fat, calories, cholesterol, or other dietary elements you may be looking to avoid. Lentils, for instance, contain 18 grams of protein per cooked cup, and beans contain about 15.
But are vegetarians and vegans likely to be getting enough protein from plant sources? Mullen said in most cases, the answer is yes.
“A healthy vegetarian/vegan is likely not deficient in protein,” she said. This concern most likely comes from a misunderstanding about how much protein we actually need to consume. Mullen said that the average healthy adult needs .8 grams of protein per kg of body weight, so for example, a 175-pound male needs about 64-80 grams of protein in a day.
“Almost every single American gets that and more,” Mullen said. Because the average American eats a lot of meat, there’s a general belief that we, in fact, require that much protein to be healthy, when in fact, we need considerably less. “A serving size of meat is about the size of a deck of cards. Most individuals consume twice that at each meal.”
In addition, she says that people tend to forget that plant-based foods can provide protein. She does caution that the veggie-curious should educate themselves on nutrition if they’re not already aware of these things. Full meals of iceberg lettuce does not a healthy diet make.
“It is important for someone who is ‘exploring’ vegetarianism or veganism to be educated in plant-based proteins — beans, quinoa, tofu, seitan, tempeh and how to eat well-balanced meals.”
So in conclusion, if you’re worried about getting enough protein on a meatless diet, chances are, you don’t have to be.
“Protein supplementation in a healthy adult is likely almost always unnecessary.”
Myth 2: You need to eat a ‘complete’ protein for it to be digested and absorbed
You may have heard the phrase “complete protein” tossed around before, but let’s back up and explain what that really means. Proteins are made up of amino acids. Of the 20 amino acids known, the human body produces 11. The other nine, referred to as “essential,” need to come from our diet.
“A food is considered a complete protein when it contains all nine,” Mullen said. And while some foods, both plant-based and not, are complete proteins, it’s not actually necessary to eat complete proteins on a daily basis in order for the amino acids to be absorbed by our bodies.
But do we need all nine in, say, every meal? That was once popular wisdom, but no more.
“It used to be believed that in order for food to be utilized as protein you had to combine foods to make a complete protein,” Mullen said. If you’re a health and fitness hobbyist, you may have heard of the term ‘protein combining,’ which is exactly that – ensuring that your plate is made up of proteins that, when combined, contain all nine essential amino acids. Some protein combining has been habitual since long before nutritional science gave us these terms – like, for instance, rice and beans, which each are incomplete proteins that together contain the full nine.
But, Mullen said, we now know that protein combining is not necessary for our bodies to make use of the nutrients.
“Your body stores a ‘pool’ of amino acids that will work together to create and package proteins.”
So, feel free to eat your rice without beans or vice-versa – as long as you’re eating a balanced diet that contains a variety of nutritious foods, chances are, you’re getting all the amino acids you need and your body can combine them on its own.
Myth 3: Protein will automatically make you lose weight
Lots of “diet” foods boast about being supplemented with protein, which will supposedly provide a direct benefit in terms of weight loss. Mullen explained the truth behind this notion:
“The reason protein gets some of its hype its ability to help with satiety and fullness,” she said. “Protein is more slowly digested which helps to keep you fuller longer. Also while exercising it is important to ensure you are getting enough protein, carbs, and fat for muscle repair and building.”
So, if you’re trying to cut back on calories for the purpose of losing weight, but you’re not getting enough protein, you’ll be more likely to feel hungry and maybe end up springing for some late-night junk food to quiet your rumbling stomach. But that said, protein doesn’t exactly deserve a weight-loss halo —- it can be overdone just like any other macronutrient.
“If you consume more than you need for protein synthesis, the macro-nutrient will be broken down and stored for energy synthesis, AKA fat, similarly to how carbohydrates are broken down and stored,” Mullen said.
And keeping in mind Mullen’s earlier point that Americans tend to eat double-sized servings of meat, anyone looking to shed pounds should be wary about protein loading.