Behaviours we encourage. Outcomes they support.

SoHow is built to shift small daily behaviours toward measurable outcomes — a more diverse gut microbiome, less chronic inflammation, steadier metabolism, and healthy ageing. Here is the research we lean on, and why the app looks the way it does.

A note on language: we talk in associations, not medical promises. Nutrition is personal — use this as a guide, not a prescription.

1. Principle 0101

   Eat 30+ different plants a week

   → A more diverse gut microbiome

   Diversity — not any single 'superfood' — is what feeds a wider range of gut microbes. Plants here includes vegetables, fruit, nuts, seeds, whole grains, herbs and spices. Works with any diet.

   Evidence: American Gut Project (2018): people eating >30 distinct plant types per week had significantly more diverse microbiomes than those eating ≤10.

   Why the app tracks food variety, not just calories.

2. Principle 0202

   Include fermented foods regularly

   → Lower systemic inflammation

   Kefir, kombucha, kimchi, sauerkraut and live yogurt introduce live microbes and are associated with less inflammation.

   Evidence: Stanford Fermented Foods Trial (2021): a high-fermented-food diet raised microbial diversity and dropped 19 inflammatory proteins, including IL-6.

   Why the roadmap includes a Ferment meter.

3. Principle 0303

   Give the gut a 12–14h overnight rest

   → Better metabolic health, gentler on the gut lining

   A nightly fasting window gives the gut time for its 'cleaning crew' microbes to tidy the lining — associated with lower inflammation and better metabolic markers.

   Evidence: Time-restricted eating literature (Spector/ZOE framing). Extended 24–48h fasts are flagged with a 'check with your provider' note.

   Why fasting is gentle by default (16:8), not extreme.

4. Principle 0404

   Choose less ultra-processed food

   → Better satiety and less chronic inflammation

   Ultra-processed foods are associated with a degraded mucosal lining and disrupted fullness signals. The useful metric here is quality, not calorie count.

   Evidence: UPF / NOVA literature — we keep this framing associative, not medical.

   Why quality signals sit alongside macros in the log.

5. Principle 0505

   Eat the rainbow

   → More polyphenols — 'fuel' for beneficial microbes

   Brightly coloured plants are rich in polyphenols, which act as prebiotics for good gut microbes.

   Evidence: Polyphenol / prebiotic research — reflected in an upcoming rainbow meter.

   Why colour variety is a signal, not a rule.

6. Principle 0606

   Personalise — there is no universal perfect diet

   → The rhythm that leaves you sharpest

   People respond very differently to the same meal. SoHow adapts to your data rather than pushing one plan on everyone.

   Evidence: PREDICT 1 & 2: up to a 10-fold difference in blood-sugar and blood-fat responses to identical meals. TwinsUK: identical twins share only ~34% of gut microbes — lifestyle matters more than genetics.

   Why the AI companion (soon) will suggest one doable next move, not a rigid plan.

Landmark studies

• American Gut Project (2018)
  McDonald D, et al., mSystems, 2018. Basis for the 30-plants-a-week idea.
• Stanford Fermented Foods Trial (2021)
  Wastyk HC, et al., Cell, 2021. Fermented diet ↑ diversity, ↓ IL-6 and 18 other inflammatory markers.
• PREDICT 1 & 2 (2020)
  Berry SE, et al., Nature Medicine, 2020. Largest in-depth nutrition-response study to date.
• TwinsUK (Spector, King's College London)
  ~15,000 twins over 30 years. Gut is largely environmental and dietary, not mainly genetic.