Plant vs. Animal Protein Sources - What's The Difference?

Foods high in protein, such as beans, meat, dairy products, are sitting on a table.

Understanding the difference between plant-based and animal-based protein sources is a significant consideration for many. With growing awareness of health, environmental, and ethical factors, your preference will likely vary compared others .This post briefly highlights the differences between protein sources that are animal versus plant-based.

First: Understanding Protein Quality

Protein quality broadly represents three main attributes in foods: total amount of amino acids, amount of essential amino acids, and ease of digestibility. The easier a food is to digest, the easier time your gut can extract the amino acids and absorb them. The protein quality is often measured by a PDCAAS scale/nutritional value. (source)

The Difference: Essential Amino Acids

Nine out of the twenty amino acids are essential. These amino acids must be consumed in the diet because the human body cannot make them. Animal-based food sources typically have all of the essential amino acids your body cannot produce, making them a complete protein. Meat, seafood, and dairy products are all complete proteins and contain all the essential amino acids.

Plant-Based Proteins – The Difference Might be Incomplete!

When it comes to choosing plant-based foods high in protein, protein quality should be considered. Some examples of complete plant-based proteins are soy products (tofu, tempeh), hemp seeds, amaranth, nutritional yeast. Many plant based proteins are not complete proteins, meaning they do not contain all the essential amino acids. If you’re prioritizing plant-based foods, you’ll want to consider adding 2-3 foods that together are complimentary proteins, meaning that the foods alone are missing essential amino acids, but together, provide all the essential amino acids.

Graph of protein quality of varying foods from a research study. — Image/Data Source: Rutherfurd SM, Fanning AC, Miller BJ, Moughan PJ. Protein digestibility-corrected amino acid scores and digestible indispensable amino acid scores differentially describe protein quality in growing male rats. *J Nutr*. 2015;145(2):372-379. doi:10.3945/jn.114.195438

Examples of Plant-Based Complementary Protein Pairings

Rice and Beans
Legumes (lentils, etc) and Nuts
Peanut Butter and Bread
Hummus and Pita

The Bottom Line: You can get your daily need of protein by consuming both animal and plant protein. If you don’t want to eat foods from animals, it’s possible to meet your needs with only plant protein – just make sure you are consuming complimentary proteins if the foods are missing some essential amino acids! If you’re looking for more individual support in food choices or altering your protein intake, working with a dietitian is beneficial. The Nutrition Prof offers 1-1 dietitian services virtually. You can also sign up for my email newsletter for more nutrition education and special offers on classes!

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