By Dr. Sanchari Sinha Dutta, Ph.D. Reviewed by Lauren Hardaker Jun 18 2025 How many almonds or walnuts must you snack on to transform your gut? New research reveals the real, modest impact and why most healthy guts resist big changes. Study:  The effects of nut intake on gut microbiome composition and gut function in adults: a systematic review and meta-analysis. Image credit: Natallia Ploskaya/Shutterstock.com A systematic review and meta-analysis of clinical trials published in the journal