If you look on the market today, you can find pea protein and other plant-based protein sources everywhere. These are often marketed as a more digestible alternative to dairy-sensitive consumers.
What these companies don’t tell you is that there’s a big biological cost to opting for plant-based protein powder instead of animal-based.
Let’s dive into the other side of the story and see how plants stack up against animal protein on different health fronts.
1. Digestibility
When you eat protein, your stomach and intestines have to break it down into a usable form.
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Animal Proteins (meat, eggs, dairy) are usually quick and easy for your body to digest, because our bodies have long been wired to consume animal products (1).
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Plant Proteins (peas, beans, grains) can be harder to digest, because they can contain fiber and other plant parts that slow digestion.
Plant proteins are marketed as more digestible because some people are sensitive to dairy.
But many people who label their symptoms as lactose intolerance actually have a sensitivity to A1 milk (i.e., the regular dairy products you’ll find at the supermarket).
A2 milk comes from older breeds of cows and has a slightly different protein that many people tolerate better.
2. Absorption & Bioavailability
Bioavailability is a fancy word for “how much of that protein actually gets into your body.”
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Animal proteins have very high bioavailability. That means if you eat 20 grams of protein from animals, your body might absorb 18–19 grams.
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Plant proteins are lower. If you eat 20 grams of pea protein, for example, your body might only absorb 16 grams.
Why? Plants have things like “anti-nutrients” (phytates and lectins) that can block absorption. So overall, animal proteins are more bioavailable (2).
3. Amino Acid Profile
There are 20 amino acids, and 9 of them are “essential,” which means your body can’t make them — you must eat them.
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Animal proteins are “complete.” They have all 9 essentials in good amounts. Eggs, meat, fish, and dairy check all the boxes.
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Most plant proteins are “incomplete.” A single plant source can lack several essential amino acids. Peas, for instance, are low in methionine, an essential amino acid that helps detoxify your liver and prevent fat buildup around it.
Summary
Digestibility: Animal protein (particularly A2) wins due to plant protein’s digestion-slowing components.
Absorption: Animal protein has much higher bioavailability than plants, which need to be heavily processed to improve absorption.
Amino Acid Profile: Animal protein is complete; most plant proteins lack several essential amino acids (3).
So, you can eat all the plant protein you want, but the reality is that animal-based protein powder does more for your body than the same amount of plant-based protein powder. Now you know!
Works Cited
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Ajomiwe, N., Boland, M., Phongthai, S., Bagiyal, M., Singh, J., & Kaur, L. (2024). Protein Nutrition: Understanding Structure, Digestibility, and Bioavailability for Optimal Health. Foods, 13. https://doi.org/10.3390/foods13111771.
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Connolly, G., Hudson, J., Bergia, R., Davis, E., Hartman, A., Zhu, W., Carroll, C., & Campbell, W. (2023). Effects of Consuming Ounce-Equivalent Portions of Animal- vs. Plant-Based Protein Foods, as Defined by the Dietary Guidelines for Americans on Essential Amino Acids Bioavailability in Young and Older Adults: Two Cross-Over Randomized Controlled Trials. Nutrients, 15. https://doi.org/10.3390/nu15132870.
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Day, L., Cakebread, J., & Loveday, S. (2021). Food proteins from animals and plants: Differences in the nutritional and functional properties. Trends in Food Science & Technology. https://doi.org/10.1016/j.tifs.2021.12.020.
