Research

Hormonal

At higher doses (30% of energy), whey protein elicits a significantly greater insulinogenic response than soy protein, whereas at lower doses (15% of energy), both proteins produce similar insulin responses and have no differential effect on plasma glucose.

If you are healthy and normal weight, you can use either whey or soy protein for post-workout or meal supplementation without worrying about blood sugar spikes. At moderate amounts (around 15g protein), they behave the same. If you consume larger amounts (30g+), whey will trigger a higher insulin response than soy, but this did not negatively impact blood glucose levels in this study. For Asian Indians at higher risk for Type 2 Diabetes, moderate doses of either protein are equally effective for glucose homeostasis.

GoodQualifiesHIGH confidence
In conclusion, at higher doses, whey protein has a greater insulinogenic response, compared to soy protein, and exhibits a dose-response effect. However, at lower doses, whey and soy protein elicit similar insulinogenic responses, making them equally effective protein sources in relation to glucose homoeostasis.
Sucharita Sambashivaiah et al. · Journal of Nutrition and Metabolism · 2023

Why this rating

Randomized, double-blind, crossover trial with adequate sample size (n=15) and rigorous statistical analysis (RMANOVA), though limited to healthy normal-weight Asian Indian males.

Source

The Effect of Soy and Whey Protein Supplementation on Glucose Homeostasis in Healthy Normal Weight Asian Indians

Sucharita Sambashivaiah et al. · Journal of Nutrition and Metabolism · 2023

DOI 10.1155/2023/2622057

crossover · n=15Cited 4×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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