In general, plant-based proteins have fewer essential amino acids7, according to Mike T. Nelson, CSCS, CISSn, MSME, Ph.D., a nutrition and fitness educator specializing in human performance. “Essential amino acids are the ones that are going to trigger the repair and the building process8 and muscle, and what’s commonly called muscle protein synthesis (MPS),” says Nelson.
Vegan proteins that are low in one or more of these essential amino acids are typically deemed “incomplete proteins.” This means that many plant-based foods—including most types of nuts, seeds, and legumes—are lower in the essential amino acids (like leucine or lysine) that your body needs and generally have a lower PDCAAS score7, which is used to measure a food’s protein quality.
Nelson advises eating more vegan protein sources or combining different types of plant-based proteins with unique amino acid profiles to fill in the gaps and create a complete protein.
That being said, it’s totally possible to fit enough of these amino acids into a vegan or vegetarian diet9 unless you’re not eating enough protein or calories overall. The key is to add more diversity to your diet by enjoying a variety of vegan protein sources rather than eating the same two or three foods on repeat.
