Plant-based protein sources

Updated May 16, 2021

In recent years the conversation around plant-based diets and protein has intensified. Dietary protein in general is part of the daily buzz: “I’ve got to have some protein at lunch;” “I didn’t eat enough protein today;” and “Do you want to add protein to that bowl/burrito/salad/wrap?”

A 2014 survey conducted by the market research firm Mintel showed that even a few years ago, a quarter of Americans were consuming more protein than they had in the previous year (Mintel 2014). Today, we are shifting away from animal protein, as plant-based diets grab the spotlight on our plates and on our menus—with vegetables from kale to cauliflower, grains from farro to quinoa, and legumes from garbanzos to lentils.

Why the Shift to Plant-Based Protein?

In the 1980s and 1990s, consumers considered fat “bad” and carbohydrates “good.” The Food Guide Pyramid told us to base our diets on carbohydrates. By the early 2000s, we were realizing that excessive consumption of carbohydrates—specifically, refined carbohydrates—actually wasn’t so good for us. Diets high in refined carbohydrates increase the risk of type 2 diabetes and heart disease (Augustin et al. 2015). We were still confused about the pros and cons of fat, however, so protein seemed like the best replacement for the carbohydrates.

Today, plant–based diets and proteins are trending. Food trend watchers predict continued interest in new vegetables and new ways of preparing them, emphasizing plant–based eating and “flexitarianism” (Innova 2015; Webb 2015; Whole Foods 2015). Vegetables like beets and carrots—and not just vegetarian staples like beans and rice—are edging out meat to fill the center of the plate at restaurants across the country (Adler 2015).

See also: Bending American Food Culture

What’s Driving Interest in Plant-Based Diets and Protein?

Concerns about the sustainability of the food supply, feeding our ever–growing population, and animal and human health top the reasons why consumers are reconsidering meat as their primary protein source (Pimentel & Pimentel 2003). More land is required to raise animals than to grow plants. Animal protein requires much more water to produce, and animal waste generates a lot of methane that’s responsible for significant greenhouse gas emissions.

In addition, antibiotic–resistant bacteria are a growing public–health concern, because the majority of antibiotics used in the United States are for animal production, not for treating human diseases (CDC 2016). Reducing our consumption of animals could lighten our carbon footprint, reduce water consumption and ease the risk that antibiotics will be overused and trigger outbreaks of antibiotic–resistant pathogens. A 2015 report by Friends of the Earth called out chain restaurants for their role in the problem of antibiotic resistance (FOE 2015), and some restaurants are responding by re–evaluating how their food is raised.

Sustainability in the world of food service is the focus of an initiative that The Culinary Institute of America and the Harvard T.H. Chan School of Public Health have collaborated on since 2014. Called Menus of Change, the initiative brings together chefs and other leaders in food service to work on improving the nutrition and sustainability of foods served in restaurants and cafeterias (CIA 2016). Shifting emphasis from animal protein to plant protein is one of the top priorities.

Isn’t Plant-Based Protein Incomplete?

When people talk about protein, they usually mean animal protein: beef, fish, lamb, pork, chicken and dairy products. Yet they usually confuse protein the food with protein the nutrient—which is in all food. Christopher Gardner, PhD, professor of medicine at Stanford University and director of nutrition studies at the Stanford Prevention Research Center, reminds consumers that meat has no monopoly on protein: “If they ate almonds, they got protein. If they ate hummus and carrot sticks, they got protein. If they ate raspberries, they got protein. Not much in the raspberries, but everything has protein.”

Humans use 20 amino acids to make proteins. All kinds of things in the body are made up of protein: muscles, of course, but also organs, bones and hair. Of those 20 amino acids, nine are “essential,” which means we can’t make them ourselves so we have to get them from food. Animal foods, milk and meat have the essential amino acids in proportions that are optimal for humans, so those proteins are called “complete.” Plants also contain all the essential amino acids, but the proportions are somewhat less optimal. We call those proteins “incomplete.”

Gardner says the biggest myth about protein consumption is that certain amino acids are lacking in plant foods and available only in animal foods. “All plant foods have all 20 amino acids,” he says. Gardner compares the proportions of amino acids in plant foods to the letters in a Scrabble game. There are lots of E’s, A’s and R’s in a bag of Scrabble letters, but few Z’s and Q’s. Z’s and Q’s are like the essential amino acids that are relatively less abundant in plant foods.

The amino acid lysine, for example, occurs at a relatively low level in grains like wheat and corn when compared with animal–based foods. But grains do indeed have lysine, just as a bag of Scrabble letters has a Z and a Q. If you have several bags of Scrabble letters, you can spell any word you want. Similarly, if you consume enough protein, you can make any body protein you need. Says Gardner: “How often do people get 2—3 bags’ worth of Scrabble letters in amino acids? In the U.S., almost every person does, every day.” When people eat meat or dairy or eggs at every meal and snack, he says, “they end up getting many bags of Scrabble letters’ worth of amino acids, of which most get converted to fats and carbohydrates.”

Do Athletes Get Enough Protein in a Plant-Based Diet?

Christine Rosenbloom, PhD, RDN, CSSD, FAND, nutrition professor emerita at Georgia State University and a sports dietitian, says, “Some athletes shun carbohydrates and focus on protein, but carbs are needed to fuel performance. The body’s number–one need is for energy, so if carbohydrate or fat intake is limited, protein will be used for energy, and that is a waste of good protein.” She adds that it’s important to think about how protein fits into the context of the overall diet.

Part of the reason for our shift to plant protein is that consumers realize getting enough protein isn’t as much of a concern as we used to think. Vegetarian athletes, including professional tennis stars Venus and Serena Williams, know that animal protein isn’t the only way to build muscle and maximize endurance. Rosenbloom points out that most athletes get enough protein. She thinks only vegan athletes need to pay more attention to their protein intake.

See also: What’s the Story on Complete and Incomplete Proteins?

Putting Plant-Based Protein and Animal Protein in Context

Since protein is not our only concern, we need to ask what else about a food is beneficial or detrimental. Legumes, seeds and nuts are high in protein and also provide fiber, vitamin E and protective phytochemicals. Beef is high in protein but also saturated fat. Ham is high in protein but also sodium. Choosing the best protein sources should include considering what other nutrients come with them.

Gardner points out that if we don’t get enough fiber in our diets, the microbiota (gut bacteria) that can reduce the risk of chronic diseases aren’t fed and don’t thrive. Fiber is found only in plant foods. Legumes, beans and peas are excellent packages of protein and fiber. According to data from the National Health and Nutrition Examination Survey (NHANES), only about 8% of Americans eat legumes daily, but the more beans and peas people eat, the higher their intake of fiber is, as well as their intake of important vitamins and minerals such as folate, magnesium, iron and zinc (Mitchell 2009). A recent study of French adults (Camilleri et al. 2013) showed that those with higher plantprotein intake had overall healthier diets and met their nutrient needs better. The researchers suggested that with protein food sources, the context of the protein relative to other nutrients in the “food protein package” (and not only the protein amount) should be considered.

Do Americans Eat Enough Plants?

According to the 2015—2020 Dietary Guidelines, Americans meet or exceed recommended intakes of meat, poultry and eggs at every age (HHS & USDA 2015). However, most of us don’t meet recommendations for seafood intake or for plant proteins like legumes (beans and peas), nuts, seeds or soy products. Data from NHANES show that Americans get 62% of their protein from animal foods (46% from meats, 16% from dairy) and just 30% from plant foods (Pasiakos et al. 2015).

Our plates don’t yet match USDA’s MyPlate or Harvard’s Healthy Plate, both of which recommend making half your plate vegetables and fruit, and eating more legumes (USDA 2016; Nutrition Source 2016). The Food and Agriculture Organization of the United Nations also wants us to increase our plant–protein intake rather than relying on animal protein. The UN declared 2016 the International Year of Pulses. FAO points out that pulses, another name for legumes, are nutritious, inexpensive and critical for worldwide food security and sustainability (FAO 2016).

See also: 5 Big Benefits of Plant-Based Eating

Putting the Flex in Flexitarian

Flexitarianism, from a word mashup of flexible and vegetarian, has been trending for years. The focus is on eating plant foods and being vegetarian some to most of the time—not on avoiding meat. It’s about seeing meat as more of a bit player in the diet, adding flavor, texture and interest. Meat doesn’t have to be totally avoided, but it’s definitely not the main event. U.S. News and World Report rated the flexitarian diet among the “Best Diets Overall” in 2016 (USNWR 2016). Flexitarianism is similar to some of the healthiest world cuisines, including Mediterranean fare and the traditional cooking of Asia, which are plant–focused but not totally vegetarian.

See also: Have Your Beans and Some Chicken, too

Are Vegetables the New Meat?

Looking at restaurant menus in 2016, you would think so, and home cooks can take some tasty ideas from the current trends. The shift toward plants is clear at restaurateur José Andrés’s new–concept U.S. restaurant Beefsteak at three locations in the mid–Atlantic region. It is named for the beefsteak tomato, not the cut of meat, and vegetables are the stars of the menu, in bowls and salads such as the cleverly named Frida Kale and the When in Romaine. It’s not vegetarian; it’s vegetablecentric, devoted to “the unsung power of vegetables.”

Le Verdure, which means “vegetables” in Italian, is part of New York’s Eataly. Le Verdure also features veggiecentric dishes, including A Selection of Warm Vegetables and Farro Salad in a Nebbiolo Vinaigrette. At Al’s Place in San Francisco, which Bon Appétit Magazine named America’s Best New Restaurant in 2015, Chef Aaron London offers seasonal vegetables and fruit, in dishes such as a Chilled Green Bean Casserole With Burrata, Tomato, Basil and Pickled Padrons. At Al’s Place, meat appears almost exclusively in the “Sides” section of the menu. Nonvegetarian Pago in Salt Lake City pays tribute to the carrot in its Carrot Tasting: Raw Carrot, Carrot Confit, Carrot Pickle, Carrot Chips and Carrot Mascarpone.

See also: Video Recipe: The Protein Flip With Lentils, Lentil Bolognese

Vegetables Replace Steaks and Roasts

Some of the shift to plants is happening at nonvegetarian restaurants, but vegetarian and vegan menus have also never been more interesting. Forget the traditional mixed grill of sausages, chicken, pork and beef. Vedge in Philadelphia has a grill section on its menu with plant–based items such as Wood Roasted Carrot With Pumpernickel, Sauerkraut, Carrot Mustard and Carrot Kimchee. There is no meat to be found. Chef Amanda Cohen’s vegetarian Dirt Candy restaurant in New York City celebrates a different vegetable in each entrée. “Tomato” is a Tomato Cake With Smoked Feta and Tomato Leather, and “Broccoli” is Grilled and Smoked Broccoli Dogs With Broccoli Kraut and Mustard Barbeque Sauce.

Veggie Burgers 2.0

Just as broccoli can now be a hot dog, vegetables can be burgers. Thankfully, the days of the bland, dry veggie burger are history. Today, veggie burgers generally fall into one of three categories: completely plant–based imitations of meat; blends of meat and vegetables; or completely new combinations of vegetables and grains that resemble burgers only because they are shaped into patties.

Beyond Meat and Impossible Foods have developed plant–based burgers for consumers and restaurants that look, behave and taste remarkably like meat. The James Beard Foundation recently concluded its second annual Blended Burger Project contest. The Foundation collaborates with The Mushroom Council to encourage chefs to get creative and make delicious burgers more sustainable, since mushrooms have a much lower carbon footprint than beef and other meats.

The winners—five chefs who develop and put a meat—mushroom blended burger on the menu at their restaurants—will have the honor of cooking at the James Beard House. Most of the chefs use very finely diced and roasted mushrooms in the blend, which are great in burgers because they add moisture and have umami. (You know that savory taste from meat? That’s umami.) Watch for these blended burgers to start popping up on menus.

Our kids are already getting a taste of blended burgers. This year Sodexo, the food service management company, introduced meat–mushroom burgers at 250 schools they sell meals to. In taste tests, 85% of kids liked the blended burger better than the old burger (Karst 2015).

Chef Brooks Headley of Superiority Burger has worked for years to develop a secret–recipe combination veggie burger (perhaps using grains and legumes). When GQ magazine named it Best Burger of the Year in 2015, it beat out burgers made of meat. Even at restaurants with meat–centric menus, veggie burgers are being reinvented. April Bloomfield’s Salvation Burger in New York features a burger made of carrot, with tomato chutney and garam masala.

The Rise of Plant–Based World Cuisines

If a restaurant served “Mediterranean cuisine” 20 years ago, chances are that it offered the foods of Italy or maybe Spain. Today, North African foods and flavors are trending (Watrous 2016; NRA 2016). Sources for Mediterranean cuisine in the United States have shifted south to Tunisia and Egypt, and east to Lebanon, Israel and Turkey.

The influence of Chef Yotam Ottolenghi, through his U.K. restaurants and especially his colorful cookbooks, is a big reason. His food is bold and flavorful, with influences from around the Mediterranean—vegetable–focused but not vegetarian. Chef Alon Shaya, who pioneered the vegetable–as–roast trend with his Whole Roasted Cauliflower With Sea Salt and Whipped Feta at Domenica in New Orleans, recently opened Shaya, which features “vegetable–centric Modern Israeli cuisine.”

In Washington, D.C., fast–casual Little Sesame has turned hummus into a restaurant concept. The restaurant offers hummus bowls topped with green salad, sumac and honey dressing, served with pita. At the grocery store, have you noticed that hummus manufacturer Sabra now offers 14 varieties of hummus?

Crickets, Pea Protein and Aquafaba, Oh My!

Will crickets catch on as sustainable protein sources? Compared with other animals, crickets require less space and water to raise, making them environmentally more sustainable (FAO 2013). Crickets and other insects are staples in some parts of the world, including Asia and Central and South America, but until recently the “ick factor” prevented most Americans from trying them. Some companies, including Bitty Foods, Chapul and Exo, avoid the ick by turning cricket flour (dried, ground crickets) into familiar foods like cookies and protein bars. Others, like Marx Pantry, embrace the ick, offering whole dried crickets, ants and even scorpions. How much protein is there in a cricket? One ounce of cricket flour has 7 grams.

Also sustainable but more familiar, pea protein is making its way into foods and supplements, including Beyond Meat’s burger. One study on pea protein showed it had the same effects as whey protein on muscle after resistance training (Babault et al. 2015). Legumes, including chickpeas, lentils and black beans, are appearing in pasta. Black bean spaghetti, for example, has more protein, fiber, calcium and iron than regular spaghetti, and less carbohydrate.

Perhaps an unexpected result of using more garbanzo beans (also known as chickpeas) is that cooks have become super creative lately with one of the most unlikely of ingredients:
the gooey, sticky water drained from canned garbanzo beans. No kidding. It has been coined “aquafaba” and can be whipped into virtually anything you would use egg for. It makes fluffy meringues and mayonnaise, and it’s an excellent egg replacer in baked goods from cakes to macaroons. Aquafaba even has a discussion group on Facebook.


The Recommended Dietary Allowance for protein is 0.8 gram per kilogram of body weight per day, a number devised to meet the needs of almost all healthy adults (IOM 2006). That’s equivalent to 0.36 g of protein per pound of body weight per day. Evidence suggests that Americans’ protein intake ranges from 1—1.3 g per kg per day, well above the RDA (Fulgoni 2008).

Another way of looking at protein intake is as a percentage of total calories. Recommendations are for 10%—35% of calories to come from protein, or between 50 and 175 g of protein per day for the average adult. It is estimated that Americans are in that range, getting 14%—16% of calories from protein (Phillips et al. 2015).


The Recommended Dietary Allowance for protein is the same for athletes as for all healthy adults. The Dietary Reference Intakes committee (which establishes the RDAs) concluded that “no additional dietary protein is suggested for healthy adults who undertake resistance or endurance exercise.” The Academy of Nutrition and Dietetics suggests that protein intake in the range of 1.2—2 grams per kg per day is appropriate for athletes; it also says there isn’t enough evidence to suggest that protein supplementation enhances athletic performance (Thomas, Erdman & Burke 2016).

Christopher Gardner, PhD, director of nutrition studies at the Stanford Prevention Research Center, points out that finding “optimal” protein intake will always be difficult, because different people of different sizes train for different sports. Since athletes need to consume more food and therefore more calories, they usually don’t have any difficulty getting adequate protein. In a small study of male college athletes, subjects perceived that their protein needs were significantly higher, and they had protein intakes above the RDA (Fox et al. 2011).

Sports dietitian Christine Rosenbloom, PhD, RDN, CSSD, FAND, says, “Most athletes get enough protein, but they don’t always distribute protein in the best way.” She recommends that athletes consume protein more evenly over three meals a day to maximize benefits, and she suggests eating about 20g of protein after a weight training session.


Animal and plant foods both have nutritional upsides and downsides. Meat is a great source of readily absorbed minerals like iron and zinc, and fatty fish contain omega–3 fatty acids. On the other hand, meats are high in saturated fat, and processed meats like salami and ham are also high in sodium.

Protein–rich plant foods, especially beans, peas, nuts and soy products, are relatively high in iron and zinc, but those minerals are less well absorbed. You can maximize iron absorption by eating beans, for example, with a source of vitamin C like fruit or tomato salsa.

Plant foods may be lower in one or more essential amino acids relative to animal foods, but as Christopher Gardner, PhD, of Stanford points out, that isn’t a downside when you are consuming enough calories. Plant foods are also rich in fiber, which helps lower cholesterol and keep your microbiota and digestive tract healthy, and they’re rich in protective phytochemicals, the biologically active compounds found only in plants.


As we see vegetables replacing meat, we also see them replacing carbohydrates. Is cauliflower the new kale? Actually, cauliflower has been trending for a while now. Last year, the cauliflower pizza crust was all over food blogs and social media. This year, cauliflower rice has joined the faux carbohydrate trend. To make cauliflower rice, simply grate raw cauliflower, or pulse it in the food processor until it’s the size of rice or large couscous. Then, use it raw in salads, or cook it briefly to soften it before using.

If 2016 will be remembered as the year of “Pokemon Go,” it will also go down as the year of spiralized vegetables. Tools and gadgets that transform vegetables into strands and curls have been flying off store shelves. Creative home cooks and chefs alike are experimenting with spiralized zucchini, sweet potatoes and butternut squash as pasta substitutes, while spiralized beets, green peppers and cucumbers are showing up in salads and soups.

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Adler, T. 2015. Are vegetables the new meat? One writer assesses the chef-driven,
plant-centric gastronomic boom. Vogue. Accessed August 4, 2016.
Augustin, L.S.A., et al. 2015. Glycemic index, glycemic load and glycemic response:
An international scientific consensus summit from the international carbohydrate
quality consortium (ICQC). Nutrition, Metabolism & Cardiovascular Diseases, 25,
Babault, N., et al. 2015. Pea proteins oral supplementation promotes muscle thickness
gains during resistance training: A double-blind, randomized, placebo-controlled
clinical trial vs. whey protein. Journal of the International Society of Sports
Nutrition, 12
(1), 3.
Camilleri, G.M., et al. 2013. Plant and animal protein intakes are differently associated
with nutrient adequacy in the diet of French adults. The Journal of Nutrition,
(9), 1466-73.
CDC (U.S. Centers for Disease Control and Prevention). 2016. Antibiotic use in food
producing animals. Accessed August 4, 2016.
CIA (Culinary Institute of America). 2016. Protein plays: Food service strategies
for our future. Accessed May 11, 2016.
FAO. 2013. Edible insects: Future prospects for food and feed security. Accessed
August 4, 2016.
FAO (Food and Agriculture Organization of the United Nations). 2016. 2016
International year of pulses. Accessed August 4, 2016.
FOE (Friends of the Earth). 2015. Chain reaction: How top restaurants rate on
reducing use of antibiotics in their meat supply. Accessed August 4, 2016.
Fox, E.A., et al. 2011. Perceived protein needs and measured protein intake in collegiate
male athletes: An observational study. Journal of the International Society of
Sports Nutrition, 8
, 9.
Fulgoni, V.L. 2008. Current protein intake in America: Analysis of the National
Health and Nutrition Examination Survey, 2003-2004. American Journal of
Clinical Nutrition, 87 (5), 1554S-57S.
HHS & USDA (U.S. Department of Health and Human Services and U.S.
Department of Agriculture). 2015. Dietary Guidelines for Americans 2015-2020,
8th ed. Accessed August 4, 2016.
Innova. 2015. Top ten trends for 2016: “Clean eating” trend inspires a backto-
basics approach. Food Ingredients First. Accessed August 4, 2016.
IOM (Institute of Medicine). 2006. Dietary Reference Intakes for Energy,
Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids
Washington, D.C.: National Academies Press.
Karst, T. 2015. Sodexo brings mushroom-beef burgers to schools. The Packer.
Accessed August 4, 2016.
Mintel. 2014. Protein fever: High protein is proving to be more than just a fad—
but will it change the way we eat? Accessed August 4, 2016.
Mitchell, D.C. 2009. Consumption of dry beans, peas, and lentils could improve diet
quality in the US population. Journal of the American Dietetic Association, 109 (5),
NRA (National Restaurant Association). 2016. What’s hot: 2016 culinary forecast.
Accessed August 4, 2016.
Nutrition Source. 2016. Healthy eating plate & healthy eating pyramid. Harvard T.H.
Chan School of Public Health. Accessed August 4, 2016.
Pasiakos, S.M., et al. 2015. Sources and amounts of animal, dairy, and plant protein
intake of US adults in 2007-2010. Nutrients, 7 (8), 7058-69.
Phillips, S.M., et al. 2015. Commonly consumed protein foods contribute to nutrient
intake, diet quality, and nutrient adequacy. American Journal of Clinical Nutrition,
(Suppl.), 1346S-52S.
Pimentel, D., & Pimentel, M. 2003. Sustainability of meat-based and plant-based
diets and the environment. American Journal of Clinical Nutrition, 78 (3, Suppl.),
Thomas, D.T., Erdman, K.A., & Burke, L.M. 2016. Position of the Academy of
Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports
Medicine: Nutrition and athletic performance. Journal of the Academy of Nutrition
and Dietetics, 116
(3), 501-28.
USDA (U.S. Department of Agriculture). 2016. MyPlate. Accessed August 4, 2016.
USNWR (U.S. News & World Report). 2016. U.S. News & World Report reveals the
2016 best diets rankings. Accessed August 4, 2016.
Watrous, M. 2016. North African flavors heat up. Food Business News. Accessed
August 4, 2016.
Webb, D. 2015. Popular nutrition trends for 2016. Today’s Dietitian, 17 (12), 26.
Accessed August 4, 2016.
Whole Foods. 2015. Whole Foods Market experts forecast top 10 food trends for
2016. Accessed August 4, 2016.

Sanna Delmonico, MS, RDS, CHES

"Sanna Delmonico, MS, RDN, CHE, is an associate professor at the Culinary Institute of America where she teaches food safety and nutrition. She previously led programming for the CIA Healthy Kids Collaborative and the CIA-Harvard Healthy Kitchens, Healthy Lives Continuing Medical Education Conference. Prior to joining the CIA, she was an instructor at Santa Rosa Junior College where she co-coordinated the dietetic technician program. Sanna develops delicious, seasonal recipes and writes about food and nutrition for publications, including IDEA Fitness Journal. She lives in Napa, California, and is a home winemaker."

1 Comment

  1. Margaret G. on March 18, 2021 at 3:49 pm

    Great article with lots of good suggestions and accurate information. You know your subject matter well, obviously. I would just add that I think it is important to be clear, especially for non-nutrition trained people who may be reading this, that vegetables (and fruits) ARE in fact carbohydrates themselves. They are being used as “faux” grains, not faux carbs. There is so much incorrect or misleading nutritional information in our world today, including the faction that says all carbs are bad. Being clear that fruits and veggies are carbs is an important part of dispelling that myth. Thanks again for a great read.

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