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SoHow app iconScience & research

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

The research behind the behaviours — why it matters to you, and how SoHow is built around it.

≤ 10 plants / weeklower diversity30+ plants / weekhigher diversity
American Gut Project · 2018 · plant variety vs microbial diversity

American Gut Project (2018)

McDonald D, et al., mSystems, 2018. ~10,000 participants, one of the largest citizen-science microbiome datasets ever collected.

What they found

People eating 30+ different plant types in a week had a measurably richer, more diverse gut microbiome than those eating 10 or fewer — regardless of whether they identified as vegan, omnivore or somewhere in between. A more diverse microbiome is associated with better digestion, a stronger immune response, and more resilient mood and energy.

Why it matters to you

If you already eat 'healthy' but rotate the same 8–10 ingredients, your gut is likely under-fed on variety. Small swaps — a new herb, a different grain, a handful of seeds — nudge that number up fast.

In the app
  • Variety counter: every distinct plant (including herbs, spices, nuts and seeds) is a point toward a weekly 30.
  • Rotation nudges when you're repeating the same foods day after day.
  • Diet-agnostic: works alongside meat, fish, keto or Mediterranean eating.
BaselineAfter 10 weeksIL-6 and 18 other markers of inflammation
Stanford Fermented Foods Trial · 2021 · 19 inflammatory markers ↓

Stanford Fermented Foods Trial (2021)

Wastyk HC, et al., Cell, 2021. 10-week randomised trial comparing a high-fibre diet with a high-fermented-foods diet.

What they found

The fermented-foods arm — kefir, kombucha, kimchi, sauerkraut, live yogurt — increased microbial diversity and lowered 19 inflammatory proteins, including IL-6, a marker linked to long-term metabolic and cardiovascular risk. Chronic low-grade inflammation is one of the quiet drivers of how you feel year to year.

Why it matters to you

You don't need a fermentation hobby. One small serving a day — a spoon of kimchi, a glass of kefir, a live yogurt — is enough to start shifting the signal.

In the app
  • Ferment logging with a simple 'servings this week' indicator (roadmap: Ferment meter).
  • Prompts that suggest a fermented pairing alongside meals you already eat.
  • Tracked as a quality signal — not another calorie to police.
identical mealtime →blood responseup to 10× variation
PREDICT 1 & 2 · 2020 · same meal, different responses

PREDICT 1 & 2 (2020)

Berry SE, et al., Nature Medicine, 2020. 1,000+ participants, continuous glucose and blood-fat responses to identical standardised meals.

What they found

Two people eating the exact same muffin can have blood-sugar and blood-fat responses that differ by up to 10-fold. Generic 'good' and 'bad' food lists ignore this. What spikes your neighbour may barely move you — and vice versa. Personal response, not the label on the package, is what actually shapes your energy, hunger and long-term metabolic health.

Why it matters to you

This is permission to stop chasing someone else's perfect diet. The meal that leaves you sharp, satisfied and steady is data — and that data is personal.

In the app
  • Post-meal check-ins (energy, hunger, mood) tied to what you actually ate.
  • Optional Apple Health integration for glucose, sleep and heart-rate signals.
  • AI companion (soon) that spots your personal patterns and suggests one doable next move — never a rigid plan.
Twin ATwin B~34% shared microbes~15,000 twins · 30 years
TwinsUK · King's College London · gut ≈ lifestyle, not genes

TwinsUK (Spector, King's College London)

~15,000 twins followed for 30 years — one of the longest-running twin cohorts in the world.

What they found

Identical twins share ~100% of their DNA but only ~34% of their gut microbes. That gap is lifestyle: what you eat, how you sleep, how you move, the antibiotics you've taken, the stress you carry. It's the strongest evidence we have that the gut is not a genetic sentence — it's largely something you shape.

Why it matters to you

You are not stuck with the gut you were born with. Small, consistent behavioural shifts move the needle more than genetics do.

In the app
  • Behaviour-first design: streaks for variety, ferments and overnight rest, not weight.
  • Gentle progress view that shows how your rhythm changes over weeks, not days.
  • Private by default: your food and health signals are yours — Enhanced AI is opt-in and off by default.

Our editorial rule

If a claim isn't backed by a credible reference, it doesn't ship. We use phrases like associated with, linked to, and emerging research suggests — and we avoid words like cures, treats, prevents, or guarantees. Your health is yours; SoHow is a nudge in a good direction, not a diagnosis.

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