Macro partitioning

Animal protein improves muscle mass compared to non-soy plant proteins (rice, chia, oat, potato) and plant-based diets, while soy protein is equivalent to milk protein for muscle mass.

If you are using plant protein, soy is just as good as animal protein for building muscle. Other plant proteins (rice, pea, oat, potato) may be less effective, so consider combining them or supplementing with soy or animal protein if muscle mass is a priority.