In This ArticleView AllIn This ArticleWhat Is Protein?Why Do You Need Protein?Sources of ProteinCan You Eat Too Much Protein?
In This ArticleView All
View All
In This Article
What Is Protein?
Why Do You Need Protein?
Sources of Protein
Can You Eat Too Much Protein?
Proteinis one of the major components of a healthy, functional body. “Protein is a macronutrient that every cell in our body needs. Proteins are made up of building blocks called amino acids, and protein is found in every cell throughout our body, so an adequate amount of protein intake is important for keeping our muscles, bones and tissues healthy,” says Kristen Smith, M.S., R.D.N., a spokesperson for theAcademy of Nutrition and Dietetics. Other macronutrients include carbohydrates and fat.
Bone density is a health consideration that has been linked to protein intake for decades. “In the ’80s and ’90s, there was a school of thought that dietary protein was bad for bones, so if you ate a lot of especially animal sources of protein, people thought that your bones may be weaker and put you at risk for fracture,” Bihuniak says. She worked on a 2015 study in theJournal of Clinical Endocrinology, titled “The Effect of Whey Protein Supplement on Bone Mass in Older Caucasian Adults,” that examined the effect of whey protein, which is in dairy products and typically found in powder form. The study found that while there were no present improvements in bone density, there were no negative consequences of dietary protein on the bones. According to Bihuniak, it helps disprove that old hypothesis.
The biggest difference between animal- and plant-based sources of protein is the presence of “complete” proteins. Complete proteins contain all nine essential amino acids. They include milk, pork, beef, eggs, poultry and fish. While the majority of these sources are animal products, soy foods, such as tofu, are plant-based alternatives. “Amino acid composition is the biggest thing,” Bihuniak says. “Some [animal-based protein sources] tend to be higher in certain amino acids like leucine, which is important for muscle protein synthesis, but you can meet your needs with plant protein sources if you eat a variety.” She adds that animal-based proteins can be easier to digest.
For decades, a long-held myth asserted thatvegetariansandveganshad to combine specific foods if they wanted to form a complete protein. “When the rise of vegetarianism came out in the ’60s and ’70s, it was very much commonplace to discuss the idea of combining certain foods. So you had to have a piece of whole-grain bread with peanut butter to get your ‘complete’ food. You had to eat beans and rice to make a complete protein, and that carried on for a long time,” Caspero says. “We recently found out that plant foods do contain all of the essential amino acids. They just contain limiting amounts of some of them.” For example, broccoli contains a small amount of the essential amino acid lysine. Though you could get the recommended amount of essential amino acids from eating nothing but broccoli, that’s hardly sustainable.
Smith recommends to “consume a variety throughout the day every week. I think in general with nutrition people get focused on one or two foods that they may think is healthy or that they feel comfortable consuming, and really trying to choose a variety of foods will help with that ultimate balance and nutrition profile.” If you eat only one or two plant-based sources of protein, you are likely limiting the amount of essential amino acids that your body needs.
Looking to pack your plate with more protein? It can be found in a variety of sources that you can incorporate into any meal of the day. Three ounces of roasted, skinless chicken breast is a leaner alternative to red meat, and has about 23 grams of protein, for example. The same amount of turkey breast contains similar levels of protein, and it’s low in fat. Seafood options include shrimp, tuna, halibut and cod. Non-meat animal-based choices include egg whites and Greek yogurt, which can replace sugary cereals at breakfast.
Plenty of plant-based options can help vegetarians and vegans meet their protein needs. “I think the absolute biggest myth that I hear a lot is that you have to eat animal-based protein in order to get complete proteins,” Caspero says. Bihuniak points to lentils, chickpeas, black beans, edamame, tofu, quinoa and nut butters (such as almond and cashew butters). Tofu and edamame are derived from soybeans and are rich in other nutrients, such as iron, calcium, folate, vitamin K and fiber.
Some vegetables, including spinach, Brussels sprouts, asparagus, artichokes, potatoes and sweet potatoes, contain small amounts of protein.“Plant-based proteins are not only nutritionally amazing, but they also contain all these other benefits that you’re just not going to be able to find in an animal-based protein,” Caspero says. “Someone following a plant-based diet can consume adequate essential amino acids when they consume a variety of plant-based protein sources throughout the day. It just takes a bit more planning,” Smith says. Spreading out your protein during the day has also been shown to be beneficial for muscle protein synthesis. Smith recommends swapping out a meat-centric meal for a plant-based meal every once and a while to get that variety.
While many Americans are concerned about getting enough protein, they are more likelyconsuming too much. “If you’re including protein with most meals and with some snacks, you’re likely consuming an adequate amount,” Smith says. Bihuniak adds: “You really have to restrict your diet to not meet your body’s protein needs.” Thedaily amount of dietary proteinrecommended for adults is 0.8 gram per kilogram of body weight, or just over 7 grams for every20 pounds of weight. For a 140-pound person, for example, that equals about 50 grams of protein per day. “That number is going to increase the more that you are active. [For] endurance athletes, that might pop up to about 1.2. Maybe the higher end is about 1.5 if you’re doing a lot of strength workouts. But I do think that the average person also overestimates how active they are.”
Your protein needs can change, however, if you are looking to lose weight.“Eating dietary protein is what we consider to be protein sparing, meaning the idea that when we lose weight, we don’t just lose fat,” Caspero says. “When we lose weight, we’re losing a lot of things in the body, and we lose about 10% of our muscle mass, or protein, as we lose weight.”
Eating more protein during active periods, such as around the time you work out, can buffer some of the natural loss that occurs. Higher protein foods also tend to be more satiating, which means that you are more likely to stay full longer. This can lead to a curbed appetite, resulting in less overeating and potentially weight loss.
The Bottom Line
In order to get more sources of healthful protein in your diet, incorporating variety into every meal of the day is essential. If you’re looking to increase intake, Smith recommends making sure at least a fourth of your plate includes a protein source, as well as substituting that midday bag of chips with protein-rich snacks, such as nuts, yogurt and cheese. And while many meat sources are considered complete proteins, experts recommend being mindful of the saturated fat found in red meat.
“We don’t just eat single nutrients. We eat food,” says Caspero. “If I’m eating black beans, yes, I’m getting protein. But I’m also getting a lot of insoluble fiber. I’m getting antioxidants. I’m getting other things that are in that food.” Many plant-based sources of protein also contain these healthful nutrients, such as fiber and antioxidants. “It’s important we consider what else is in the food,” she says.
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