Plant-Based Protein: What You Should Know

Can Plant-Based Protein Compete with Animal Protein?

Plant-based proteins differ from animal proteins in their amino acid profile and digestibility. Combining different sources can improve the amino acid profile (DGE; SGE).

How Is Protein Quality Measured?

Amino Acid Profile

Proteins are built from amino acids. Nine of them are indispensable (essential): the body cannot produce them on its own. “Complete” proteins contain all essential amino acids in sufficient quantities.

Animal proteins: Generally complete Plant-based proteins: Often have limiting amino acids

Bioavailability

The DIAAS (Digestible Indispensable Amino Acid Score) rates a protein by how much of each indispensable amino acid is available after digestion in the small intestine, compared with a reference pattern (FAO, 2013). A score below 100 means that at least one indispensable amino acid is in shorter supply.

The values vary depending on variety, processing and scoring pattern. Mixtures of different plant sources can reach a higher score (Herreman et al., 2020).

Why Should You Combine Plant Protein Sources?

Combining different plant protein sources compensates for limiting amino acids and creates a complete profile. The classic example: legumes + grains. The amino acids complement each other and together form a complete profile.

Modern protein blends use this principle:

• Pea + hemp: pea protein covers the lysine requirement but is low in methionine plus cysteine. Hemp protein is the other way round (Herreman et al., 2020). Hemp protein also provides magnesium, iron and zinc.

What Does the Research Say?

Study on Vegan and Mixed Diets

An intervention study (Hevia-Larraín et al., 2021, Sports Medicine) compared 19 men who habitually follow a vegan diet with 19 men on a mixed diet. Both groups did weight training twice a week for 12 weeks. Protein intake in both groups was supplemented to around 1.6 g per kg of body weight per day, with soy protein for the vegans and whey for the mixed-diet group.

Result: Both groups gained lean leg mass, and there was no difference between the groups. The participants were untrained young men.

The Leucine Question

Leucine is one of the indispensable amino acids. On average, plant-based proteins contain less leucine than animal proteins: 7.1% versus 8.8% of protein.

Leucine content as % of protein:

• Whey: 11.0%
• Pea protein: 7.2%
• Soy protein: 6.9%
• Hemp protein: 5.1%

To obtain the same amount of leucine as from 25 g of whey (2.7 g), a laboratory analysis found that about 38 g of pea protein or 40 g of soy protein is needed (Gorissen et al., 2018; Pinckaers et al., 2021).

How Digestible Is Plant-Based Protein?

The DIAAS of most plant sources is lower than that of meat, eggs and milk. For potatoes it is higher, for soybeans about the same (SGE, Proteins fact sheet, 2022). Plant foods also often contain tannins, phytates or trypsin inhibitors, which can impair the bioavailability of the proteins. Soaking, cooking, fermenting and sprouting can reduce the content of these substances (SGE, Proteins fact sheet, 2022).

Plant-based protein sources contain:

• No lactose
• No casein (purely plant-based protein source)

Practical Recommendations

Protein Amount

The SGE recommends 0.83 g of protein per kg of body weight per day for adults aged 19 to 65. Whether vegans should aim for a somewhat higher intake is under discussion. According to the SGE, further research is still needed on this (Vegan nutrition fact sheet, 2022).

Vary Your Sources

Don’t rely on a single source. Combine different legumes, grains, nuts, and protein powders.

Focus on Quality

For protein powders:

• Combination of different sources (e.g. pea + hemp)
• Compare protein content per 100 g and the ingredient list
• Minimal additives
• No artificial sweeteners

Conclusion

With sufficient amounts and a combination of different sources, plant-based protein sources can contribute to protein supply. Differences in the amino acid profile can be reduced by combining different sources (DGE). An additional advantage of plant-based protein sources: they provide dietary fiber. bunaroba protein powder contains 12 g fiber per 100 g, hemp protein even 21 g per 100 g. Whey protein contains 0 g fiber.

Sources:

• Hevia-Larraín V, Gualano B, Longobardi I, Gil S, Fernandes AL, Costa LAR, Pereira RMR, Artioli GG, Phillips SM, Roschel H (2021). High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports Medicine, 51(6), 1317-1330. DOI: 10.1007/s40279-021-01434-9
• Gorissen SHM, Crombag JJR, Senden JMG, Waterval WAH, Bierau J, Verdijk LB, van Loon LJC (2018). Protein content and amino acid composition of commercially available plant-based protein isolates. Amino Acids, 50(12), 1685-1695. DOI: 10.1007/s00726-018-2640-5
• Pinckaers PJM, Trommelen J, Snijders T, van Loon LJC (2021). The Anabolic Response to Plant-Based Protein Ingestion. Sports Medicine, 51(Suppl 1), 59-74. DOI: 10.1007/s40279-021-01540-8
• Herreman L, Nommensen P, Pennings B, Laus MC (2020). Comprehensive overview of the quality of plant- and animal-sourced proteins based on the digestible indispensable amino acid score. Food Science & Nutrition, 8(10), 5379-5391. DOI: 10.1002/fsn3.1809
• Nosworthy MG, Franczyk A, Neufeld J, House JD (2023). The in vivo and in vitro protein quality of three hemp protein sources. Food Science & Nutrition, 11(11), 7264-7270. DOI: 10.1002/fsn3.3652
• Burd NA, Beals JW, Martinez IG, Salvador AF, Skinner SK (2019). Food-First Approach to Enhance the Regulation of Post-exercise Skeletal Muscle Protein Synthesis and Remodeling. Sports Medicine, 49(Suppl 1), 59-68. DOI: 10.1007/s40279-018-1009-y
• Rutherfurd SM, Fanning AC, Miller BJ, Moughan PJ (2015). Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats. The Journal of Nutrition, 145(2), 372-379. DOI: 10.3945/jn.114.195438
• FAO (2013). Dietary protein quality evaluation in human nutrition. Report of an FAO Expert Consultation. FAO Food and Nutrition Paper 92. Rome. fao.org
• SGE Swiss Society for Nutrition (2022). Vegan nutrition. Fact sheet, September 2022 (in German). sge-ssn.ch
• SGE Swiss Society for Nutrition (2022). Proteins: quality and content in foods. Fact sheet, October 2022 (in German). sge-ssn.ch
• DGE German Nutrition Society (as of 10 September 2025). Selected questions and answers on protein and indispensable amino acids (in German). dge.de