We took a look at popular protein myths to see if there was any truth behind them.

Shaun Dreisbach
May 05, 2020
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Protein is hot, hot, hot. It's the nutrient we all think we need more of—even though, we probably don't. Almost 66% of Americans report they're trying to get more protein in their diet, according to an International Food Information Council survey.

And while protein is important, our body uses it to build muscle and make hormones amongst other key functions, more protein doesn't mean your diet is healthier. There are a lot of myths out there around protein and the best ways to consume it. Here, we sort it all out for you and decipher fact from fiction.

1. "Complete proteins" are best.

That's a myth. Proteins are made up of amino acids—20 of them total, each with specific, important functions. Some (called non­essential amino acids) your body can make on its own, but there are nine essential amino acids that it can't—and these must be consumed through your diet. Complete proteins are foods that contain all nine of those essential amino acids, including animal proteins, like fish, poultry, eggs and dairy—although there are some vegetarian sources, including soy, quinoa and chia seeds, that do too. For a long time, most plant proteins were considered inferior because they weren't "complete." "But now we know that as long as you eat a varied diet, it doesn't really matter," says Isabel Maples, M.Ed., R.D.N., a spokesperson for the Academy of Nutrition and ­Dietetics. "Your body will join essen­tial amino acids from one meal with those from another to get the amount it needs."

2. Animal protein is easier to digest than foods like beans. Plus, beans contain harmful lectins.

Yes and no. Your body does break down and use the amino acids from animal proteins more readily than those from plant sources. But that doesn't necessarily make them better. Beans have other things going for them, like fiber, potassium and magnesium—all nutrients Americans don't get enough of. You can also relax about the whole lectin thing. Here's the deal: Lectins are a specific group of proteins found in a slew of foods, but beans and other legumes happen to have higher amounts of them. They can potentially interfere with carb digestion, causing gastrointestinal issues, and promote inflammation in the body—thus all the internet hullabaloo about these so-called "anti-nutrients." But lectins are only problematic when beans are eaten raw or under cooked, and even then the science is iffy, says Maples. (Plus, when was the last time you ate a pile of uncooked lentils or black beans? Exactly.) And more recent research suggests lectins may actually be beneficial—feeding your good gut bacteria and fending off harmful bacteria and viruses.

3. It's tough to get enough B12 and iron if all of your protein comes from plants.

True-ish. "B12 is an issue because animals are the only dietary sources of the vitamin. So that's one case where if you're vegan—and not having eggs or dairy, which are rich in B12—it's worth taking a supplement," says Maples. Iron is much less of a concern. "Even though the type of iron in plants like beans, legumes and whole grains isn't as absorbable as the kind in meat, you can improve that by pairing a food containing vitamin C with a nonanimal protein," she adds. Think: black beans with tomatoes and bell peppers. A tasty way to get your dose.

4. Processed meat is as bad as smoking cigarettes.

The truth isn't quite as sensational as the headlines. "The World Health Organization concluded that processed meats are a class one carcinogen with the same consistency of evidence as tobacco. That doesn't mean they both have the same level of risk, though," explains Mozaffarian. For example, according to the Centers for Disease Control and Prevention, eating 50 grams of processed meat a day (about 1 hot dog) ups the odds for colorectal cancer by 18 percent—while smoking cigarettes raises lung cancer risk by 1,500 to 3,000 percent. And let's put that in perspective. The average risk of developing colorectal cancer over a lifetime is 5 percent. Multiply that 5 percent baseline risk by 18 percent and you get just an added 0.9 percent, for an overall risk of 5.9. As long as you keep the amount you eat reasonable, there's no need to nail-bite about it.

5. Plant-based sources of protein are healthier than animal sources.

This one's sort of true—but stay with us for a minute here. "If you look at observational studies, people who eat more animal protein tend to have a higher risk for some diseases, such as cancer, diabetes, stroke and heart disease, and those who eat more plant protein have lower odds," says Mozaffarian. "But all of those studies conclude that the difference is very likely due to the other good-for-you compounds in plants, rather than animal sources ­being bad for you—with the exception of processed meats." In other words, it doesn't have to do with the protein. Amino acids are amino acids, whether you get them in chicken or lentil form. The edge that veg sources have appears to be due to things like antioxidants and fiber that animal sources lack. So a balance of both types is fine.

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