What is the low-FODMAP diet?

A structured, temporary elimination diet that reduces fermentable carbohydrates (FODMAPs) that trigger IBS symptoms, then reintroduces them to find your personal triggers. It runs in three phases and isn't meant to be permanent.

Does the low-FODMAP diet work for IBS?

Randomized trials show the elimination phase reduces symptoms in a majority of people with IBS. It works best with a dietitian and must be followed by reintroduction — long-term strict restriction can reduce beneficial gut bacteria.

What foods are high in FODMAPs?

Common ones include onion and garlic, wheat, apples and pears, legumes, honey, and sugar alcohols (sorbitol, mannitol). Many are otherwise healthy fibers, which is why the diet is temporary.

July 2, 2026 · Gut Symptoms · By Craig Rouskey

The Low-FODMAP Diet

Quick answer: The low-FODMAP diet is a structured, temporary way of eating that reduces certain fermentable carbohydrates — Fermentable Oligo-, Di-, Monosaccharides and Polyols — that can trigger gas, bloating and pain in people with IBS. It runs in three phases: strict elimination (2–6 weeks), structured reintroduction, and personalization. It is not a forever diet, and it’s best done with a dietitian.

If you have IBS, you’ve probably heard of FODMAPs — and probably also heard it explained badly. It is one of the most evidence-backed dietary approaches for IBS, but it’s also widely misused as a permanent “avoid these foods” list, which it was never meant to be.

Here’s what FODMAPs actually are and how the diet is supposed to work.

What FODMAPs are

FODMAPs are short-chain carbohydrates that are poorly absorbed in the small intestine. They draw water in and are rapidly fermented by gut bacteria, producing gas. In a sensitive gut, that stretching and gas translate into bloating, cramping and altered bowel habits. Common sources include onion and garlic, wheat, certain fruits (apples, pears), legumes, and sugar alcohols.

Note the irony: FODMAPs are often healthy fibers that feed good bacteria. The low-FODMAP diet isn’t about them being bad — it’s about temporarily calming a reactive gut.

The three phases

1) Elimination — cut high-FODMAP foods for 2–6 weeks to see if symptoms settle. 2) Reintroduction — add FODMAP groups back one at a time to find your specific triggers and thresholds. 3) Personalization — return to the widest possible diet, avoiding only what genuinely bothers you.

Randomized trials show the elimination phase reduces symptoms in a majority of people with IBS. But phases 2 and 3 are the point — long-term strict restriction can actually reduce beneficial gut bacteria.

Why it isn't forever

Because FODMAPs feed good microbes, staying in strict elimination long-term can lower levels of beneficial bacteria like Bifidobacteria. That’s why the diet is designed to widen again, and why it’s best run with a dietitian rather than self-imposed indefinitely.

The goal isn’t a permanently narrow diet — it’s knowing your own triggers so you can eat as broadly as your gut allows.

Find your pattern

Match, don’t guess. The free Gut-Brain Axis Assessment reads how your system behaves and points you to the matched GoodOnes formula.

References

Halmos EP, Power VA, Shepherd SJ, Gibson PR, Muir JG. A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology. 2014;146(1):67–75.
Staudacher HM, Whelan K. The low FODMAP diet: recent advances in understanding its mechanisms and efficacy in IBS. Gut. 2017;66(8):1517–1527.
Cryan JF, O’Riordan KJ, Cowan CSM, et al. The microbiota–gut–brain axis. Physiol Rev. 2019;99(4):1877–2013.

This article is for education and does not diagnose, treat, cure, or prevent any disease. GoodOnes™ formulations support everyday gut function; they are not a substitute for medical care. If your symptoms are severe, persistent, or accompanied by warning signs, see a licensed clinician.

About the author

Craig Rouskey · CEO, Flore Inc. & Microbiome Scientist

MSc Molecular Biology, Microbiology, Biochemistry & Immunology (SIU). Craig is the scientist behind the GoodOnes™ targeted-probiotic line, built on a longitudinal dataset of 23,447 sequenced microbiomes. Former leadership at Renegade Bio, Pando Nutrition, and Bionascent; TEDxBellevue speaker on citizen science and precision health.