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Plant Protein: A Friend of Human & Environmental Health

As someone who has spent most of his life eating a health-conscious vegetarian, vegan, or plant-based diet, getting sufficient protein was often something I needed to think about.

If I got a dollar for every time I have gotten some form of the question or accusation: “Do you get enough protein?”, I would be a wealthy man. I have heard this from people who knew both very little or very much about human biology. A vegetarian or vegan diet can easily meet dietary protein requirements as long as caloric needs are met and a variety of foods are eaten.

Possible Health Benefits of Plant Protein

According to the American Dietetic Association, appropriately planned vegetarian or vegan diets are nutritionally adequate and may provide prevention or act as a treatment for certain diseases. A plant-based diet is appropriate for all people and life stages, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes, according to the Academy of Nutrition and Dietetics.

A vegetarian or vegan diet can both treat and lower risk from:

Plant Protein vs. Animal Protein

One of the benefits of animal protein sources is that animal sources of protein contain a large amount of complete protein and essential micronutrients. Most meat-eaters do not need to think twice about getting a complete protein intake and enough of it.

What is a “complete protein?”

Proteins consist of building blocks called amino acids. There are 9 amino acids our bodies cannot produce and they must be included in our diet. All animal sources of protein contain all of them, while most plant-based sources do not contain all 9 in one item alone. However, by eating a diet full of a variety of plant foods, humans can easily attain all 9 essential amino acids and enough overall protein.

"Plant proteins alone can provide enough of the essential and non-essential

amino acids, aslong assources of dietary protein are varied and caloric intake is

high enough to meet energy needs. Whole grains, legumes, vegetables,seeds and

nuts all contain both essential and non-essential amino acids. You don’t need to

consciously combine these foods (“complementary proteins”) within a given

A person eating a plant-based diet must also be mindful to get enough nutrients that are readily available in animal products. These nutrients include:

Although all of these nutrients are available in a variety of plant foods, those choosing a vegan or vegetarian diet must be mindful to regularly eat all of these foods, or take them as a dietary supplement.

According to the American Dietetic Association, “the best nutrition-based strategy for promoting optimal health and reducing the risk of chronic disease is to wisely choose a wide variety of foods. Additional nutrients from supplements can help some people meet their nutrition needs as specified by science-based nutrition standards such as the Dietary Reference Intakes.”

Figure 1 - Protein Density: Animal vs. Plant

Sources of Plant Protein

It is important to eat a wide variety of plant protein sources and it is equally important to find protein sources you enjoy eating. This list contains a few sources and it is recommended to try a few new ones in a variety of dishes you like so you’ll stick with eating them in the long-term.

  • Black beans and rice

  • Kidney beans

  • Dark, leafy greens such as broccoli, spinach, asparagus artichokes potatoes, brussels sprouts, and kale

  • Lentils

  • Chickpeas

  • Tofu or soybeans

  • Hemp seeds

  • Quinoa

  • Mushrooms

  • Sprouted grain bread such as Ezekiel bread

  • Seeds

  • Nuts

How Much Protein Do We Need?

The National Academy of Medicine recommends adults get a minimum of 0.8 grams (g) per kilogram of body weight. Multiply your weight in pounds (lb) by 0.36: that’s how many grams of protein you should be getting each day at a minimum. Therefore, if you weigh 150 lb, you’d aim for 54 g of protein daily.

To think of it another way, protein should make up between 10%-35% of your daily calorie intake.

Environmental Consideration

Our food system (primarily production) is responsible for 26% of global GHG emissions. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with notably less environmental damage. Compared to omnivorous and carnivorous diets, vegetarian diets utilize less water and fossil fuel resources and use lower amounts of pesticides and fertilizers. Here’s an example to really put all of this into perspective.

Compared to producing one kilogram of protein from beef, producing one kilogram of protein from kidney beans requires:

  • 18x less land

  • 10x less water

  • 9x less fuel

  • 12x fewer fertilizers

  • 10x fewer pesticides

I don’t know about you, but that data makes it clear to me that reducing protein intake from animal sources will be paramount in our global efforts to reduce environmental destruction. According to multiple sources, meat production makes a significant contribution to anthropogenic (created by humans) greenhouse gas emissions, including carbon dioxide emissions, and methane and nitrous oxide production. Experts propose that reducing animal production has a greater potential to reduce greenhouse gas emissions than technological mitigation or increased productivity measures.

If that wasn’t enough, the use of antibiotics in farm animals has generated antibiotic-resistant bacteria. This resistance can be transmitted to humans through animal food consumption and is now a major health concern, causing diseases that are difficult to treat, resulting in increased death and healthcare costs.

Kid's in Nutrition's food sustainability curriculum uses the concept of an "Energy Pyramid" to teach kid's about how different foods have different levels of resource use (see Figure 3). On average, humans eat high on the pyramid, which creates a problem for the environment and our world by contributing to the impact of climate change through carbon and methane emissions. In the curriculum, we explain to the children that for a human to get energy from a cow (let’s say by eating a burger) they need all the energy from the plants, the sun, the land, and the water that the cow needed to become a cow in the first place. In addition to the energy and resources needed to create animal protein for human consumption, these same animals produce methane gas that increases atmospheric GHGs. Overall, it is better for the environment (and our health) to eat lower on the energy pyramid to reduce GHG emissions and lessen our impact on non-finite resources like land and water.

Figure 3 - KIN's Energy Pyramid: Explaining Resource-Intensive Food Choices

Conflicting Evidence

There are studies that have shown some risks to those who adopt a vegetarian or vegan diet. Nearly all of these issues come from inadequate intake of nutrients (listed above) or protein. One study showed that bone strength was reduced in vegans, which resulted in a greater risk of fracture. However, when calcium intake increased to over 525 mg/day, a greater risk of fractures disappeared. Another study found that rates of stroke were 20% higher among vegetarians compared to meat-eaters. However, the overall risk was small, equal to three extra cases per 1,000 people over 10 years. This study also found that vegetarians had lower rates of heart disease.

Limitations of many of the studies cited are that they are purely observational. For example, in the previous study, if these vegetarians chose plant-based diets because of a family history of stroke, it could be their genes driving the higher rates of stroke, not the diet.


Including more plant foods in our diets can offer benefits that extend from personal (reducing the risk of chronic disease) to planetary (lessening the environmental impact of resource-intensive foods). Variety is key. As long as you don’t consume plant-proteins from only a couple of foods, you don’t really have to devote mental energy to obtain all the amino acids that your body needs.

Furthermore, plant-based eating exists on a spectrum! You don’t have to eat only plant-based protein to obtain the benefits of a plant-based diet. You can be a plant-based eater and still include animal products such as dairy, fish, meat, and eggs in moderation. It is important to emphasize your focus on ADDING plant-based foods to your diet rather than eliminating other foods. This can be a helpful mindset and feel less overwhelming or impossible for those new to plant-based eating. As a global family, it is essential that we all participate in the journey of reducing meat consumption for the health of ourselves and the planet!

You can reach both baseline and high protein goals with a plant-based diet. KIN is here to provide you with the resources and know-how for those that want to include more plant-based foods the right way. With a little knowledge and planning, plant-based protein goals can be easy to reach! Check out KIN's resources page for more HOW TO information on incorporating more plant foods every day!

NOTE: KIN does not promote vegetarian/ vegan diets but we do believe plant proteins

can be a healthy substitute for animal proteins by lowering risks of chronic diseases and lessening the impact of climate change through the choices we make in our food system.

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