Plant Protein vs. Animal Protein: Is One Healthier Than the Other?

The choice is yours: beef or beans; lobster or lentils; steak or seitan. Do you need to pick a side, as suggested by the growing divide between the carnivorous crowd and those who limit or abstain from meat, or can you choose from all of the above depending on what you feel like eating on a given day?

There are many reasons one might choose a particular protein path, but for this article, we’re focusing on how the body processes animal proteins versus plant proteins — and the differences healthwise. A little sneak preview: Both offer our bodies benefits, and for the best of all worlds, you need not choose between plants and animals.

Ahead, discover why our bodies need protein in the first place, the ideal protein intake for you, plus the differences between how our bodies use animal products and plant-based proteins.

What Is Protein and Why Do Our Bodies Need It?

In tandem with carbohydrates and fat, protein is one of three essential macronutrients the body requires daily. Lauren Harris-Pincus, RDN, founder of Nutrition Starring YOU and author of The Protein-Packed Breakfast Club, debriefs us on some key differences:

• Carbohydrates: 4 calories per gram; broken down into glucose and used as the body’s primary energy source
• Fat: 9 calories per gram; also used as energy and to help absorb fat-soluble vitamins including A, D, E, and K
• Protein: 4 calories per gram; found in our muscles, bone, hair, and nearly every cell in the body. It’s used as a backup (and less efficient) energy source after carbs and fat, and has a wide array of other essential roles.

“Protein is responsible for many important functions in the body, including the building and repair of tissues, making hormones and enzymes, supporting immunity, regulating metabolism, and transporting nutrients and oxygen,” Harris-Pincus tells DailyOM.

Caroline Thomason, RD, a Warrenton, Virginia–based nutritionist and diabetes educator who helps women stop dieting and find confidence with food, adds that protein intake also helps with satiety. Translation: You’ll feel fuller longer after a high-protein meal than a low-protein one.

Interested in learning more? Check out Stop Unwanted Eating Behaviors in 8 Days: 8 Pillars of a Nutritious Life

The Two Types of Protein: Plant Protein vs. Animal Protein

According to the Harvard T.H. Chan School of Public Health, more than 10,000 different proteins make us “us” — in other words, make up our hair, muscles, bones, skin, and other tissues — and 20 amino acids act as building blocks to make protein “protein.” Our bodies can manufacture some of these amino acids to keep important body processes humming, but nine of them (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) are the essential amino acids, which means we must get them from food.

“Both plant and animal proteins provide essential nutrients that are important for a healthy, balanced diet,” says Frances Largeman-Roth, RDN, a Dobbs Ferry, New York–based nutritionist and author of the upcoming Everyday Snack Tray.

“Protein can come from plants or animals,” Thomason explains. “Animal sources are considered ‘complete’ proteins, while most plant-forward sources are incomplete proteins.” Complete protein sources contain all essential amino acids. Incomplete sources contain only some of the essential amino acids, and need to be combined with other protein sources to make them complete. You can build dynamic duos or teams of plant proteins, such as rice and beans together, to DIY a complete protein package.

Vegetarians aren’t typically protein-deficient in Western diets, though, and emerging research suggests that as long as you mix up the proteins and other meal components as part of your plant-based diet, there’s no need to fret about whether the exact ingredient or single meal or snack you’re consuming is “complete.” You’ll likely eat what you need over the course of a day. Additionally, we know that our bodies store amino acids, which can kick in to round out an incomplete protein. (And in 2020, pistachios were found to be a complete protein, so we’re still learning more in this space.) 

Still, there are some variances between plant and animal proteins, and how our body uses them.

Is Animal Protein Better for You Than Plant Protein?

“Plant proteins tend to come with more fiber and certain vitamins, while animal proteins tend to have more of other vitamins and minerals — like zinc, niacin, and vitamin B12 — and sometimes, certain beneficial fats,” Largeman-Roth tells DailyOM. (Case in point: the easily absorbable, heart-healthy omega-3 fats found in salmon, sardines, and mackerel.)

That plant-exclusive fiber, by the way, is a form of nondigestible carb. Since our bodies don’t have the enzymes needed to break down fiber, it passes through our gut without being digested. A whopping 95 percent of Americans are short on fiber, which is a shame since it aids in digestion, tames appetite, and supports gut health (which, in turn, benefits mental health and reduces chronic disease risk). More fiber from any source, including plant-based proteins with fiber, is a boon for well-being.

For optimal health, if you have no other restrictions — culturally, allergies, etc. — it’s wise to include a variety of both plant and animal sources in your diet because they each provide a different set of nutrients, Largeman-Roth explains. “The most recent Dietary Guidelines for Americans recommends eating a variety of protein foods, including seafood, lean meats and poultry, eggs, legumes, nuts, seeds, and soy foods.”

 

Protein is one of the three macronutrients our bodies require each day to thrive. Whether you consume animal protein or plant protein, this macro is essential to support several VIPs (very important processes) within the body.

 

The Protein Digestibility–Corrected Amino Acid Score (PDCAAS) is an indicator of protein quality. This scale takes into account a protein’s digestibility and amino acid profile. Each protein is given a percentage score, up to 100 percent, to estimate its ability to meet our body’s needs.

The PDCAAS for eggs, milk, casein, and whey all clock in at 100 percent, Largeman-Roth points out. For comparison, soy protein isolates are the only plant protein to reach 100 percent; pea protein concentrate has a score of 89 percent, chickpeas are 74 percent, and peanut butter is 45 percent.

“Animal proteins are more easily digested and absorbed by the body, making them more bioavailable,” Harris-Pincus says.

While there’s no magic wand that you can wave over all plant foods to make them easier for the body to digest or put to good use, soaking, fermenting, sprouting, cooking, and combining certain foods might be beneficial practices. If you follow a vegetarian or vegan diet, it can be a good idea to consult with a dietitian to learn the best ways to prepare food and plan meals to cover all your bases.

Some preliminary studies have suggested that more plant protein would be needed to achieve the same amount of muscle growth as animal protein provides. However, this appears to only hold true for specific populations — and much more research is required to really make a verdict about plant protein versus animal protein for muscle growth.

“Other studies have found that soy protein provided the same benefits as animal protein for strength and muscle gains. Overall, both animal and plant protein have been shown to support an increase in lean mass,” Largeman-Roth says. And both help support the aforementioned important functions within our cells.

How Much Protein to Eat Each Day

Your ideal protein intake depends on your age, activity level, and health status, Harris-Pincus tells DailyOM. Current guidelines are the same for all genders, though this is an area where further research is still needed to understand any sex-based differences around protein absorption.

The 2020 to 2025 Dietary Guidelines for Americans recommend aiming for 10 percent to 35 percent of calories from protein per day, which is a mark that can be achieved via a plant-forward or omnivorous diet, or anywhere in the middle, Thomason says. “Cultural preferences are important to consider here. Depending on one’s background, certain foods might be an integral part of their diet. Everyone should be able to include their favorite foods as part of a balanced diet,” she adds.

The recommended daily allowance (RDA) for protein is 0.8 grams per kilogram of body weight, but that’s actually the minimum to prevent deficiency versus an optimal intake, Harris-Pincus explains. And though the current suggested guidelines are the same for all adults, growing research is pointing to older adults requiring more protein than their younger counterparts, possibly between 1.2 and 2.0 grams per kilogram of body weight each day. 

A 2016 study in the journal Food & Function recommends this formula to help you dial into your particular protein needs: 

• Divide your weight in pounds by 2.2 to get your weight in kilograms (or you can use an online calculator to help you crunch the numbers).
• Multiply that number by 1 if you’re minimally active to get your ideal protein intake in grams.
• Multiply by 1.3 if you’re moderately active.
• Multiply by 1.6 if you’re very active.

If you’re a moderately active individual who weighs 150 pounds, for example, shoot for around 89 grams of protein per day. It’s important to keep in mind that this is the goal for the entire day, Largeman-Roth points out. This will not only help boost satisfaction and keep energy levels and appetite more even, but it also makes scientific sense. Mayo Clinic experts confirm that the latest science hints that we might max out the muscle-building and health-boosting benefits at around 30 to 40 grams of protein at each meal.

“So perhaps you’re having 25 grams at breakfast, 20 grams at lunch, and 30 grams at dinner, with the additional 14 grams sprinkled into a snack or two,” Largeman-Roth says, referring to that 89-gram goal example.

To give you an idea of what this might look like:

• Start the day with a three-egg omelet and two slices of wheat toast.
• Fill up at lunch with a bowl of lentil chili and an apple.
• Come dinner, enjoy 4 ounces of salmon with ½ cup cooked quinoa and a side of roasted vegetables.
• Pepper in snacks like a banana and handful of pistachios, or a carton of yogurt and berries, whenever you like.

The Bottom Line

Protein is one of the three macronutrients our bodies require each day to thrive. Whether you consume animal protein or plant protein, this macro is essential to support several VIPs (very important processes) within the body, including building and repairing tissues, bolstering the immune system, making hormones and enzymes, controlling metabolism, and transporting nutrients around the body.

For the greatest boost to the body, mix up your protein sources to score a variety of amino acids (as well as vitamins and minerals) and to keep your menu interesting. To tame your appetite and maximize the health benefits of protein, spread out your protein intake throughout your meals and snacks from morning to night.

Once you’re ready to start maximizing your menu and creating your own personal recipe for success, check out the best plant and animal protein sources.