Soy protein isolate has 80.7 g protein per 100 g with DIAAS ~0.90–0.98. A meta-analysis of 17 RCTs (Reid-McCann et al., Nutr Rev 2025) found no difference versus milk protein for muscle mass (SMD = −0.02, P = 0.80). The highest-quality plant protein powder available.
How should I track Soy protein isolate, powder?
Soy protein isolate, powder is high in protein. Plant-based foods like Soy protein isolate, powder often come with variable water content, so weighing after draining or pressing gives you the most accurate count. Tofu blocks, for example, can vary by 30% in weight depending on how much liquid they hold. A meta-analysis of 43 RCTs (Reid-McCann et al., Nutr Rev 2025) found that soy protein matches dairy protein for muscle outcomes, so the tracking precision matters just as much as with animal sources. Also watch for marinated or flavored versions — sauces add calories that are easy to miss.
