Soy protein isolate delivers 88 g protein per 100 g. A 35–40 g serving hits the leucine threshold for most adults. A meta-analysis of 43 RCTs (Reid-McCann et al., Nutr Rev 2025) confirmed soy matches dairy for muscle building. Note 1,005 mg sodium per 100 g – active individuals tolerate this well within the optimal 3–5 g daily range.
How should I track Soy protein isolate?
Soy protein isolate is high in protein. Supplement tracking comes down to two things: measuring the supplement itself and logging everything around it. For powders like Soy protein isolate, a kitchen scale beats a scoop — scoops typically deliver 10–20% more than the stated serving (Almiron-Roig et al., Appetite 2013, found portion errors of 50–200% for dense foods). For capsules and tablets, count-based tracking is simpler but still matters at multiple daily doses. The real tracking trap is what you mix supplements with — milk, fruit, or nut butter can turn a 30-calorie serving into a 400-calorie shake. Log each ingredient separately for an accurate total.