Apr 25, 2026

What to Eat on a SIBO Protocol: The Research on Low-FODMAP

By The Luna Lab Research Team · 9 min read

TLDR:

SIBO diet works on a different principle than other gut diets: it’s about not feeding the bacterial overgrowth while you’re actively treating it. Once the overgrowth is reduced, the diet becomes less restrictive.
The most-studied approach is low-FODMAP — reducing fermentable carbohydrates that bacteria readily ferment. Other approaches include the SIBO Specific Food Guide, the Bi-Phasic Diet, and the Cedars-Sinai Low-Fermentation Eating plan.
Low-FODMAP is meant to be temporary. The goal is symptom relief during treatment, not lifelong restriction. Long-term low-FODMAP can actually starve beneficial bacteria too.
Practical translation: lean into well-cooked meats and fish, low-FODMAP vegetables (zucchini, carrots, spinach, bell peppers), eggs, hard cheeses, and limited specific fruits. Significantly reduce or remove garlic, onions, beans, wheat, milk, and high-FODMAP fruits during the protocol.
Adjust based on subtype: methane-dominant SIBO (constipation) often benefits from a lower-carb-overall approach; hydrogen-dominant SIBO benefits more from straight FODMAP reduction.

Eating during a SIBO protocol works on a different principle than eating during a parasite cleanse or a gut lining reset. With parasites, the question is “am I supporting the protocol?” With gut lining repair, the question is “am I providing the raw materials and removing the inflammation?” With SIBO, the central question is more direct: am I feeding the bacterial overgrowth?

This guide covers what the research supports for SIBO diet, why low-FODMAP became the dominant approach, where it has limits, and how to think about the practical day-to-day during your Luna Lab Microbiome Balance Formula protocol.

Why SIBO is different: the FODMAP problem

Most healthy gut function depends on bacteria fermenting fiber in the colon, where it’s welcome and produces beneficial short-chain fatty acids. The problem with SIBO is that bacteria are doing this fermentation in the small intestine, where it’s not welcome and produces gas, bloating, distension, and inflammation.

The fuels that bacteria ferment most readily are a class of carbohydrates called FODMAPs — Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. They include:

Fructans — in wheat, onions, garlic, leeks, asparagus, artichoke
Galacto-oligosaccharides (GOS) — in beans, lentils, chickpeas
Lactose — in cow’s milk, soft cheeses, ice cream
Excess fructose — in apples, pears, mangoes, watermelon, honey, agave
Polyols — in stone fruits (cherries, peaches, plums), avocado in large amounts, mushrooms, sugar alcohols (sorbitol, xylitol)

Reducing FODMAPs during a SIBO protocol means reducing the fuel supply for the overgrowth. Symptoms typically improve within 1–2 weeks of starting a low-FODMAP diet during active SIBO treatment — not because anything is being healed yet, but because there’s less fermentation happening.

The research base for low-FODMAP in IBS and SIBO is strong: a 2017 systematic review in Nutrients found low-FODMAP improved overall symptoms in roughly 50–80% of IBS patients, with the effect partially explained by the substantial overlap between IBS and SIBO.

The honest case for keeping low-FODMAP temporary

Low-FODMAP isn’t a long-term diet. Done indefinitely, it has documented downsides:

It starves beneficial bacteria too. The same fermentable fibers that feed SIBO bacteria also feed the beneficial colon bacteria that produce butyrate and protect the gut barrier. Long-term FODMAP restriction has been shown to reduce microbiome diversity.
It can become orthorexic. The food list is restrictive enough that people sometimes spiral into anxious avoidance even after their symptoms resolve.
It doesn’t address root causes. Diet management makes SIBO symptoms manageable; it doesn’t treat the underlying overgrowth or motility issue. Without antimicrobial intervention and recurrence prevention, you’re managing symptoms forever.

The right framing: low-FODMAP is a tool you use during active SIBO treatment to reduce symptoms while the antimicrobial protocol does the underlying work. Once the overgrowth is reduced (typically by week 4–6 of treatment), you start carefully reintroducing FODMAPs to identify what you specifically tolerate — and the long-term goal is the most varied diet you can eat without symptoms.

Foods to lean into during SIBO treatment

Quality animal protein

Eggs, fish, poultry, beef, lamb, pork. Plain protein doesn’t feed FODMAP-fermenting bacteria. Avoid breaded preparations, sausages with onion or garlic in the seasoning, and processed deli meats.

Low-FODMAP vegetables (cooked, ideally)

Zucchini, summer squash
Carrots
Bell peppers (red, yellow, green)
Spinach, kale, swiss chard, romaine, arugula
Cucumber
Tomatoes (in moderation)
Eggplant
Green beans
Bok choy
Potato (small portions)
Olives

Healthy fats

Olive oil, avocado oil, ghee, butter, coconut oil. These don’t feed bacteria; they help stabilize blood sugar and provide gallbladder support. Avocado is technically low-FODMAP in small portions (about 1/8 of a fruit) but high in larger portions; track your tolerance.

Limited low-FODMAP fruits

Berries (strawberries, blueberries, raspberries) in moderate portions
Citrus (orange, mandarin, lemon, lime)
Banana (firm/unripe is best; very ripe banana increases in FODMAPs)
Cantaloupe
Grapes
Kiwifruit

Hard cheeses and lactose-free dairy

Cheddar, parmesan, Swiss, brie, camembert, and other hard or aged cheeses are very low in lactose and generally well-tolerated. Lactose-free milk is OK; regular cow’s milk is high-FODMAP. Almond milk and rice milk are typically low-FODMAP; oat milk varies.

Specific gluten-free grains

Rice (white or brown) is the safest bet. Quinoa is generally tolerated. Oats are low-FODMAP in small servings. Avoid wheat, barley, rye during the protocol — the fructans in these grains are major SIBO triggers.

Hydration and herbal teas

Plenty of water. Peppermint and ginger teas are excellent for SIBO — both reduce gas and support motility. Avoid sweet teas and kombucha during active treatment.

Foods to remove or significantly reduce

The big high-FODMAP triggers

Garlic in any form (raw, cooked, powdered, in sauces)
Onions of all kinds (white, yellow, red, leek, scallion whites). Scallion greens are low-FODMAP.
Wheat — bread, pasta, most crackers, soy sauce
Beans and lentils in standard portions (very small amounts of canned, rinsed legumes are sometimes tolerated)
Cow’s milk and soft cheeses
Apples, pears, mangoes, watermelon — high in fructose
Honey, agave — replace with maple syrup or stevia in moderation
Sugar alcohols — sorbitol, xylitol, maltitol (often in “sugar-free” products)
Mushrooms in larger amounts
Avocado in larger portions

The fermentation triggers

Most probiotics — especially Lactobacillus and Bifidobacterium-heavy formulas. Many people with active SIBO feel worse on probiotics during treatment. The Microbiome Balance Formula uses a balanced 10B blend timed for the PM pack to minimize this issue, but if symptoms worsen, talk to your practitioner.
Fermented foods — sauerkraut, kimchi, kombucha, kefir, yogurt. These are fantastic for general gut health, but during active SIBO, they often worsen symptoms.

Alcohol

Skip during the 30-day protocol. Alcohol disrupts gut motility (a key driver of SIBO recurrence), feeds bacterial fermentation, and works against the anti-microbial herbs you’re taking. After the protocol, occasional clear spirits (vodka, gin) without sugary mixers tend to be best tolerated for those continuing to manage SIBO.

SIBO subtype matters: hydrogen vs. methane

Hydrogen-dominant SIBO (often diarrhea or alternating)

Standard low-FODMAP works well. The bacteria producing hydrogen are typically fermenting the FODMAPs directly; reducing FODMAPs reduces gas and symptoms quickly.

Methane-dominant SIBO / IMO (often constipation)

Methane is produced by archaea (a different microorganism class) that consume the hydrogen produced by bacterial fermentation. People with methane-dominant SIBO often respond better to a lower-carb-overall approach (sometimes called “Cedars-Sinai Low Fermentation Eating”) than to strict low-FODMAP. Methane-dominant SIBO is also typically slower to treat — expect longer protocol durations.

Hydrogen sulfide SIBO (sometimes “rotten egg” gas)

Less commonly tested but increasingly recognized. Tends to respond to a lower-sulfur diet (less garlic, onion, cruciferous, eggs, certain meats) plus standard antimicrobials. If your gas has a notable sulfur smell, ask your practitioner about hydrogen sulfide testing (Trio-Smart breath test covers this).

How to handle the AM/PM Microbiome Balance Formula schedule with meals

The Luna Lab protocol is two packs per day — AM and PM. Practical timing:

AM pack: with your morning meal (or 10 minutes before). The AM pack includes ginger root and zinc that can be slightly hard on a fully empty stomach for some people; with food is fine and often better tolerated.
PM pack: in the afternoon, ideally before dinner. The PM pack includes the probiotic, which generally absorbs well outside of antibacterial herb peaks.
Space the two packs at least 4–5 hours apart for optimal coverage.
Aim for 4 hours between meals with no snacks in between if possible. The migrating motor complex (MMC) — the muscular sweep that clears the small intestine — runs only between meals and is one of the strongest defenses against SIBO recurrence. Frequent snacking inhibits it.

Frequently asked questions

How strict do I need to be on FODMAPs?

Strictness matters most for the first 2–4 weeks while symptoms are at their peak. Aim for 80–90% adherence rather than perfectionism. After symptoms calm, you can begin systematic reintroduction to identify which specific FODMAPs you tolerate.

How long do I have to eat low-FODMAP?

Generally 4–8 weeks during active treatment, then a structured reintroduction phase over 6–8 weeks where you test FODMAP groups one at a time. The end goal is the broadest diet you can eat without symptoms — which for many people post-treatment is much less restricted than they expect.

Can I do low-FODMAP and gluten-free at the same time?

Yes — these diets overlap significantly (wheat is high-FODMAP). Most low-FODMAP recipes are naturally gluten-free or easily made so.

Will I lose weight on this protocol?

Some people do (less inflammation, less bloat, more body awareness around food); some don’t. Weight isn’t the metric. How your bloating, gas, and energy track week-over-week is.

Should I avoid coffee?

Coffee itself is low-FODMAP and most people tolerate it during SIBO treatment. Black coffee or coffee with a splash of lactose-free milk or almond milk is generally fine. Sweetened coffee drinks, frappuccinos, and oat milk lattes are generally not. Limit to 1–2 cups daily and pair with extra water.

What about garlic-infused olive oil?

Garlic’s FODMAPs are water-soluble, not oil-soluble. Garlic-infused oil — if made by simmering garlic in oil and then straining the garlic out — gives you the flavor without the FODMAPs. This is a major QOL win during a low-FODMAP protocol. Same logic with onion-infused oil. Commercial garlic-infused oils (like Fody Foods) are widely available.