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Bloated at 3:45 PM. Was it lunch?

Probably not. Food takes hours to reach your colon, where gut bacteria turn it into gas, so this afternoon's bloating often started with last night's pasta. Gut Twin lines up your meals with how you feel and helps you test the likely culprit, one change at a time.

Become a beta tester Check a food for FODMAPs
Bloating: 7 out of 10Logged at 3:45 PM

Your Gut X-Ray

3:45 PM
Lunch: wheat wrapStomachBreaking down
Breakfast: porridgeSmall intestineAbsorbing nutrients
Last night: garlic pastaColonLikely fermenting, making gas

Rough times: stomach 2–4 hours, small intestine 2–6 hours, colon 1–2 days.

Your microbes set how gassy a meal gets

Onion reaches your colon in everyone. What happens next depends on your microbiome, the trillions of microbes living there: how much gas they make from it, which kind, and how fast it moves on. That's why the same meal can bloat you and leave a friend feeling fine.

Painting of a slightly bloated gut with a worried face
Your gut Lots of gas
A friend's gut A little gas

The same onion in two people. Its fiber reaches the colon in both, and the microbes living there turn it into a lot of gas or very little.

  • Fiber fans Bifidobacteria ferment fiber without making much gas.
  • Gas makers Many others turn the same fiber into hydrogen, the gas you feel.
  • Slow movers Methane makers are linked to a slower gut.

Meet your Gut Twin

A model of how your gut tends to react, built from your answers on day one. Every test you finish adds to it.

Processed food: most daysGut or nerves: openFiber: low most daysTransit: a bit slowOnion and garlic: likelyPlant variety: 9 a week
Your gutBloats some afternoons. Hard to tell why from the inside.
Your Gut Twin
How your gut feels. Built from your check-ins and tests.What your food feeds. Our estimate of which gut microbes your diet is feeding, from your food answers. Ready on day one.

Starts from your answers

A few short questions give your Twin its first ranked list of suspects.

Moves on finished tests

A suspect moves one step only when a test ends. A single day leaves the list as it is.

An estimate you can test

It reads your answers and test results, and every line on it is an estimate.

One loop, from hunch to answer

Set up once, then repeat: your Twin picks a suspect, you test it for 14 days, and the answer goes into your Twin before the next round.

Once, at the start
Answer a few short questions
Get your first Twin
Log three evenings first
  1. Step 1

    Your Twin picks a suspect

    • Onion and garlic Likely
    • Wheat Possible
  2. Step 2

    You change one thing for 14 days

    Garlic-infused oil instead of garlic
    Then garlic comes back for a few days, to check.
  3. Step 3

    You check in each evening

    How bloated were you today, from 0 to 10? 20 seconds.
  4. Step 4

    You get an answer

    Helped
    Before
    5
    Test days
    3
    Bloating about 2 points lower, out of 10. The other answers are no change, worse and unclear.
Your Twin takes the answer, then picks the next suspect

Wondering about garlic, onion or wheat?

FODMAPs are carbs that ferment in your gut and can cause gas. Our free checker tells you if one serving is high in FODMAPs, and what to swap it for.

Open the free checker
Painting of onion and garlic Garlic, 1 clove High FODMAP
Painting of olive oil Garlic-infused oil, 1 tbsp Low FODMAP

Try Gut Twin before everyone else

Build your Twin, run one test against your own days and see how it went. Then tell us how the app worked for you. We're starting with a small group.

  • Free, including your test
  • On iPhone and Android
  • About 20 seconds each evening to check in
  • Your details are used only for the beta. Privacy

We're inviting testers in small groups and will email you when your spot opens.

Become a beta tester
The Gut Twin app icon: a smiling gut bean

Made by Bliss Labs, the small team behind Skin Bliss, a skin app with over 3 million recorded installs.