FoodMarble vs Fodmi: a breath tester or a meal log?

FoodMarble and Fodmi both try to help you find the foods behind your symptoms, by different routes. FoodMarble pairs an app with a handheld breath tester: you log a food, breathe into the device, and it measures hydrogen and methane. Fodmi works from the meal itself: photograph your plate, see its FODMAPs across the six groups, and check in a few hours later on how it sat. Before you buy a breath tester, it’s worth knowing that IBS guidelines don’t recommend breath tests for finding food intolerances; the standard method is a few weeks of cutting FODMAPs back, then reintroducing them one group at a time.

We make Fodmi, so take our view with that in mind. Everything below about FoodMarble comes from its US App Store listing, which we read on 28 October 2026. Listings and prices change; check the current one before you decide. Fodmi is not affiliated with or endorsed by FoodMarble.

Side by side

	Fodmi	FoodMarble
Approach	Work out the FODMAPs you ate, then see how each meal sat	Measure hydrogen and methane in your breath after eating
What you need	Your iPhone	The app plus an AIRE breath tester, sold separately
Logging a meal	Photo, voice or text; barcode or label photos for packaged food	Log your food, then take a breath test
FODMAP content	Each meal across the six groups; more than 900 foods with the amount where each stays low	A food library and a kit that tests lactose, fructose, sorbitol and inulin
Symptoms	Check-ins a few hours after each meal, with the Bristol stool scale	Symptoms, stress and sleep logged alongside breath results
Report for your doctor	Weekly trends and a PDF report	Its listing doesn’t mention one
Devices	iPhone	iPhone and iPad
Price	Free download, full access by subscription	Free app; the breath tester is bought separately

What FoodMarble does

FoodMarble’s listing describes a personal breath tester, the AIRE 1 or AIRE 2, paired with the app. You log a food, take a breath test, record any symptoms, and see results in a few seconds. The device measures hydrogen and methane, gases made when gut bacteria ferment food, and the listing says it helps you spot potentially problematic foods. Its Food Intolerance Kit tests four FODMAP components one at a time: lactose, fructose, sorbitol and inulin.

Around the tests, the app logs your diet, symptoms, stress and sleep, and has a food library, low FODMAP recipes and challenges. It’s aimed at people with IBS, SIBO and other digestive problems.

What guidelines say about breath tests

Breath tests can show that a sugar is poorly absorbed, but poor absorption is common in people without any symptoms. For people with typical IBS symptoms, the British Society of Gastroenterology says breath tests have no role in diagnosing carbohydrate intolerance.³ FODMAPs also act together: several foods that are each fine can add up in one meal, which a single-sugar test can’t show. Our guide to tests for FODMAP intolerance explains this in more detail.

What Fodmi does

Fodmi starts from the meal on your plate. Take a photo, say what you ate, or type it. Fodmi picks out the ingredients, including hidden garlic and onion, and shows the whole meal across the six FODMAP groups, because FODMAPs from different foods add up. A few hours later it asks how the meal sat, so over a few weeks you can see which foods line up with bad days, and you can bring that pattern into the reintroduction phase. You get weekly trends and a PDF report for your doctor or dietitian, and it scans packaged food by barcode or label.

What it doesn’t do: there’s no breath test or other measurement of your body, and it’s iPhone only. How Fodmi works out its answers.

Which should you pick?

• Want to find your triggers the way IBS guidelines recommend? Cut FODMAPs back, then reintroduce them; Fodmi helps you log meals and symptoms along the way.
• Curious about your own hydrogen and methane readings? FoodMarble measures them; treat the results as a personal experiment, not a diagnosis.
• Don’t want to buy a device? Fodmi needs only your iPhone.
• Need a record of meals and symptoms for your doctor? Fodmi’s PDF report.

Whichever you choose, see a doctor first to rule out other causes, and work with a dietitian on the diet if you can. Our guide to the low FODMAP diet explains the three phases.

Frequently asked questions

Can a breath test tell me which foods trigger my IBS?

The British Society of Gastroenterology’s IBS guideline says breath tests have no role in diagnosing carbohydrate intolerance in people with typical IBS symptoms. The reliable way to find your triggers is to cut FODMAPs back for a few weeks and then reintroduce them one group at a time.

Do I need to buy anything to use FoodMarble?

The app is a free download, but its breath tests need FoodMarble’s AIRE device, which is sold separately. Fodmi needs only your iPhone.

Does FoodMarble track food and symptoms too?

Yes. Its listing describes logging your diet, symptoms, stress and sleep alongside breath tests, plus a food library, low FODMAP recipes and challenges.

Can I use FoodMarble and Fodmi together?

Yes. They don’t share data, so you would log meals in each, but some people use a breath tester for experiments and Fodmi for everyday meals.