Keep it real - reducing ultra processed foods

Your gut microbiome loves real food

A large new study from Israel, involving over 10,000 adults and published in the March 2026 edition of Nature Medicine,  has given us one of the clearest pictures yet of how everyday food choices shape the gut microbiome. The takeaway is refreshingly simple: what appears to matter most is how processed your diet is.

What the study found

• Diet influenced almost every gut microbe the researchers looked at

• Certain foods had very specific effects:

  • Coffee boosted a beneficial butyrate‑producing bacterium

  • Yogurt increased Streptococcus thermophilus

  • Milk supported several Bifidobacterium species

• But the biggest finding? Ultra‑processed foods were strongly linked to lower microbial diversity, while whole, minimally processed foods supported a richer, more resilient gut ecosystem.

Why this matters

A diverse microbiome is associated with better digestion, immunity, and metabolic health. This study shows that food quality  (especially processing level) may matter just as much as specific nutrients.

And the good news

These diet–microbiome relationships were not short-lived: they persisted over four years of follow-up. In other words: Your gut really does remember how you eat.

What this means for everyday eating

Focus on:

• Whole foods (fruit, veg, nuts, seeds, whole grains, legumes, fish, eggs, meat)

• Fermented foods like yogurt or kefir

• Minimising ultra‑processed foods where possible

Whole food spread

Reference

Segev, T., Barak, D., Zahavi, L. et al. Diet–microbiome associations in 10,068 individuals from the Human Phenotype Project to guide personalized nutrition. Nat Med (2026). https://doi.org/10.1038/s41591-026-04312-x