Plant Protein: Abundant, Complete, and Healthier

Abundant protein can be found in such plant foods as beans, peas, broccoli, lentils, peanuts, quinoa, spinach, tofu, corn, and many others. For example, a peanut butter and jelly sandwich contains more protein than a McDonald’s hamburger.¹

The quantity of protein is not the only concern—some feel that the quality of protein in plants is lacking. Authorities agree that if you eat a variety of plant foods and consume sufficient calories, then you get sufficient and complete protein—all nine essential amino acids, in the proportions needed.

• The Academy of Nutrition and Dietetics explains that “using the terms ‘complete’ and ‘incomplete’ to describe protein is misleading. They further explain that “eating a variety of plant foods will supply all the protein you need.”²
• Harvard Medical School, Mayo Clinic, Cleveland Clinic, Kaiser Permanente, NewYork-Presbyterian, the Academy of Nutrition and Dietetics, the Dietitians of Canada, the British Dietetic Association, the Dietitians Association of Australia, and others have declared a vegan diet to be not only sufficient but advantageous. They would not make this pronouncement if there were a problem with getting complete protein from plants.
• Perhaps Dr. Andrew Weil sums it up best: “You may have heard that vegetable sources of protein are ‘incomplete’ and become ‘complete’ only when correctly combined. Research has discredited that notion so you don’t have to worry that you won’t get enough usable protein if you don’t put together some magical combination of foods at each meal.”³

While Registered Dietitian Ginny Messina acknowledges that protein is not just a vegan concern, and that vegans don’t need to worry about protein, she also cautions against dismissing protein concerns in vegan diets.⁴

She notes that while severe protein deficiency diseases like kwashiorkor are not a risk for vegans this does not mean all vegans consume optimal amounts of protein, and she cautions that consistently low protein intake can negatively impact bone and muscle health over time.⁵

The most extensive study comparing vegans and meat-eaters (The Adventist Health Study 2, ongoing from 2002), examining over 70,000 subjects, found that meat-eaters consumed an average of 75.8 grams of protein daily, while vegans consumed 72.3 grams, indicating a minimal difference in total protein consumption.⁶

Interestingly, nearly 60 percent of the protein consumed by meat-eaters was derived from plant sources.⁷

According to Dr. Walter Willett, animal protein caries higher risks of mortality, heart disease, stroke, and diabetes.⁸

• Dr. Walter C. Willett is a prominent American nutrition researcher and professor at the Harvard T.H. Chan School of Public Health, and has authored several influential books on nutrition and health.

A study published in the JAMA Internal Medicine in August 2016, the largest study yet to examine the effect of different sources of protein, found that animal protein is associated with higher mortality risk while plant protein is associated with lower mortality risk.⁹

A review by Dr. Sofia Ochoa cites 42 studies showing that animal protein, but not plant protein:¹⁰

• elevates hormone-insulin-like growth factor-1 (IGF-1), which stimulates cell division and growth in both healthy and cancer cells and “has been consistently associated with increased cancer risk, proliferation, and malignancy.”
• “results in us having higher circulating levels of trimethylamine N-oxide (TMAO),” which “injures the lining of our vessels, creates inflammation, and facilitates the formation of cholesterol plaques in our blood vessels.”
• causes the overproduction of the hormone fibroblast growth factor 23 (FGF23), which damages our blood vessels, can lead to “abnormal enlargement of the cardiac muscle…and is associated with heart attacks, sudden death, and heart failure.”
• can result in the over absorption of heme iron, causing the conversion of other oxidants into highly reactive free radicals that “can damage different cell structures like proteins, membranes, and DNA” (heme iron “has been associated with many kinds of gastrointestinal cancers…”).
• can result in a higher incidence of bone fractures because of animal protein’s high concentrations of sulfur.
• contributes to atherosclerosis—“plaques of cholesterol that accumulate in the lining of our vessels.”

Dr. Garth Davis concludes that people whose diets are high in animal protein have significantly higher rates of chronic diseases and stated that “this conclusion is supported by virtually every large-scale scientific study: massive efforts that followed thousands of people over many years in multiple countries around the globe.” The diseases include:¹¹

• hypertension
• cancer
• diabetes
• heart disease
• cataracts
• diverticulitis
• diverticulosis
• inflammatory bowel disease
• gallbladder disorders
• gout
• hypertension
• irritable bowel syndrome
• kidney stones
• rheumatoid arthritis

When you eat mostly animal protein, you risk not getting enough fiber in your diet. Fiber is packaged with plant protein and does not exist in animals. While protein deficiency is rare, fiber deficiency is rampant, with only 3 percent of Americans meeting the daily minimum requirements for fiber. Most get less than half the requirement.¹²

Many people are surprised to learn that the essential amino acids, the building blocks of protein that we must get from food, are manufactured only by plants, algae, and some microorganisms. When we eat animals, we are getting essential amino acids originally made by plants, algae, and microorganisms that were then eaten by animals.¹³

Since no essential amino acids are made by animals, it’s illogical to believe we must eat animals to get them.¹⁴

For a 150-pound person (based on your ideal or healthy body weight), the RDA for protein calculates to 54 grams. The average American consumption is significantly higher.¹⁵

The Recommended Daily Allowance (RDA) is 0.8 grams of protein per kilogram of ideal or healthy body weight. A safety factor of almost double is built into the Recommended Daily Allowance. Ideal body weight is used because extra fat tissue requires relatively little protein.¹⁶ Those over the age of 60 might need more, but the research is conflicting.¹⁷

According to a PubMed study, “extra protein is not used efficiently by the body and may impose a metabolic burden on the bones, kidneys, and liver. Moreover, high-protein/high-meat diets may also be associated with increased risk for coronary heart disease due to intakes of saturated fat and cholesterol, or even cancer.”¹⁸

Vegans get their protein from the same source that the strongest animals on the planet get their protein—plants. These animals include gorillas, elephants, rhinoceroses, hippopotamuses, and horses. It’s also noteworthy that almost all the land animals we eat, namely cows, pigs, and factory chickens, get their protein from plants.

Although these nonhuman examples prove nothing specific to humans, they at least suggest that since plants alone can provide the protein needed by these animals, plants alone might also provide the protein that humans need.

Note: anecdotal evidence is not a strong form of evidence, but it can provide inspiration and perhaps show what is possible.

Kendrick Farris, Men’s Fitness Magazine calls Kendrick Farris America’s strongest weightlifter. He is 100 percent vegan,¹⁹ and adopted a vegan diet for ethical reasons.²⁰

Patrik Baboumian, at the time of this writing, still holds the world dead-lift record five years after adopting a vegan diet. He claims that his meat-free diet gave him more energy and endurance in the gym than ever before.²¹

Barny du Plessis, the 2014 amateur Mr. Universe champion, stated that after he went vegan, he “found himself in better shape than ever” and had “more energy and endurance in the gym than ever before.”²²

Although the preceding examples are from the sport of weight lifting because of its obvious connection to protein, endurance athletes need protein too. So we’ll mention that Scott Jurek, a top ultramarathon runner, is also vegan.²³