Small intestinal bacterial overgrowth, bloating
SIBO Diet
Starve the bacteria in the wrong place, in phases, without starving yourself.
- Core restriction
- Fermentable carbohydrate, staged and time-limited
- Difficulty
- ●●●●●
- Check a food
- Open the food checker
A gentle reminder. This guide is for learning, not a prescription. Therapeutic diets interact with medication and conditions, so it's worth talking to your doctor or a registered dietitian before you begin.
A tidy few pages with the food lists, meal plan and reminders — good for the fridge door or the first appointment with your dietitian.
How it works
In small intestinal bacterial overgrowth, colonic-type bacteria colonise the small intestine, where food arrives before you have absorbed it. They ferment carbohydrate on the spot, producing hydrogen or methane, which shows up as bloating within 30-90 minutes of eating rather than hours later.
Diet does not cure SIBO. It reduces the fuel supply so symptoms drop while the actual treatment — antibiotics such as rifaximin, herbal antimicrobials, or fixing the underlying motility problem — does the work.
Most protocols run in phases: a strict reduction for two to six weeks, then structured reintroduction. Staying restricted long term reduces microbial diversity and tends to make the gut more reactive, not less.
Nutrition at a glance
SIBO eating is deliberately time-limited — the diet controls symptoms while treatment addresses the overgrowth.
- Restriction phase
- 2-6 weeks
- Longer rarely helps and starves the good bacteria too
- Fermentable carbs
- Heavily reduced
- Lactose, fructans, GOS, polyols
- Meal spacing
- 4-5 hours
- Lets the migrating motor complex sweep the small bowel
- Meals per day
- 3, no grazing
- Snacking interrupts that sweep
- Fibre
- Low, then rebuilt
- Reintroduced as symptoms settle
Nutrients that often run short
- Fibre
- Calcium
- Iron
- B12
- Fat-soluble vitamins (A, D, E, K)
These are the ones worth planning for — through food where you can, and through a supplement your clinician suggests where you can't.
Key cautions
None of this is meant to frighten you off. These are simply the things that most often catch people out on this diet — the ones worth raising at your next appointment.
- Talk to a clinician
Diet alone rarely clears SIBO
Antibiotics, herbal antimicrobials or an elemental formula usually do the clearing. Diet manages symptoms and reduces relapse; used alone it can look like progress while the overgrowth persists.
- Worth testing
Malabsorption shows up in bloods
B12, iron and fat-soluble vitamins are worth checking if symptoms have run for months.
- Keep an eye on
Restriction has a shelf life
Beyond about six weeks the microbiome narrows and food fear grows. Reintroduce systematically even if it feels risky.
- Keep an eye on
Look for the underlying cause
Adhesions, hypothyroidism, diabetes-related motility problems and structural issues drive relapse. Recurrence is a signal, not a personal failure.
Used for
- SIBO confirmed by lactulose or glucose breath test
- IBS with bloating that begins soon after eating
- Post-infectious IBS and slow gut motility
- Scleroderma, diabetic gastroparesis and other conditions causing stasis
- Recurrent SIBO after adhesions or bowel surgery
What to eat
Eat freely
Protein and fat
- All plain meat, poultry, fish and eggs
- Olive oil and butter
- Hard aged cheeses
- Lactose-free dairy
Low-fermentation vegetables
- Carrot
- Zucchini
- Spinach
- Bok choy
- Cucumber
- Lettuce
- Bell pepper
- Green beans
- Tomato
Fruit
- Blueberries
- Strawberries
- Kiwi
- Orange
- Cantaloupe
- Unripe banana
Starch, if tolerated
- White rice
- Quinoa
- Sourdough spelt
- Potato
Eat with care
Test one at a time
- Small servings of oats, sweet potato or plantain
- Hard cheese versus soft — lactose load differs
- Coffee, which speeds motility for some and irritates others
- Fibre supplements — partially hydrolysed guar gum is usually better tolerated than psyllium
- Fermented foods, which help some people and inflame others
Best to skip
High-FODMAP carbohydrate
- Onion and garlic
- Wheat in quantity
- Beans and lentils
- Cauliflower
- Mushroom
- Apple, pear, watermelon
- Dried fruit
Sugars that ferment
- Honey and agave (fructose)
- Sugar alcohols — sorbitol, mannitol, xylitol
- Inulin and chicory root
- High-fructose corn syrup
- Milk if lactose intolerant
Habits
- Constant snacking, which blocks the migrating motor complex
- Alcohol during the treatment phase
Three days of meals
Day 1
- Breakfast
- Two eggs with spinach cooked in garlic-infused oil, a few blueberries.
- Lunch
- Grilled chicken over lettuce, carrot and cucumber, olive oil and lemon.
- Dinner
- Salmon, white rice, green beans.
- Snack
- A small orange. Leave four hours between eating occasions.
Day 2
- Breakfast
- Lactose-free yoghurt with strawberries.
- Lunch
- Beef and zucchini stir fry in garlic-infused oil over rice.
- Dinner
- Roast turkey, mashed potato with lactose-free milk, roasted carrot.
- Snack
- Handful of walnuts.
Day 3
- Breakfast
- Omelette with bell pepper and aged cheddar.
- Lunch
- Rice noodle bowl with prawns, bok choy and ginger.
- Dinner
- Lamb chops, quinoa, sauteed spinach.
- Snack
- Kiwi.
Getting started
- 1
Test before you restrict. Bloating has many causes, and an empirical low-FODMAP diet before a breath test can produce a false negative.
- 2
Pick one framework — low FODMAP, SIBO Specific Food Guide, or Bi-Phasic — rather than stacking all three into a diet of six foods.
- 3
Space meals four to five hours apart so the migrating motor complex can sweep the small intestine between meals.
- 4
Treat the cause: adhesions, hypothyroidism, opioids, PPIs and diabetic neuropathy all cause relapse regardless of diet.
- 5
Set a reintroduction date at the start. Two to six weeks strict, then structured challenges.
Common mistakes
- Staying in the restriction phase for months and ending up with a fragile, narrow diet and a less diverse microbiome.
- Grazing all day, which prevents the cleansing waves between meals.
- Taking prebiotic fibre or high-dose probiotics during the strict phase without a plan.
- Retesting endlessly rather than tracking symptoms.
- Assuming methane-dominant overgrowth responds like hydrogen — the treatment and the food triggers differ.
FAQs
Can diet alone clear SIBO?
Rarely. Diet controls symptoms; antimicrobials plus motility support usually do the clearing. Diet without treating the underlying stasis tends to relapse.
Elemental diet — is it worth it?
A two-week elemental formula has high reported eradication rates but it is expensive, unpleasant and hard to sustain. It is usually a last resort after antibiotics fail.
Why did I feel better then worse?
Symptom relief in week two followed by relapse in week six is the classic pattern when the motility problem behind the overgrowth has not been addressed.
Stacking with other diets
- SIBO and low FODMAP overlap almost completely; low FODMAP is the best-evidenced backbone.
- SIBO plus keto is very compatible — both cut fermentable carbohydrate — but keto's inulin-sweetened products are a trap.
- SIBO plus histamine intolerance is common; overgrowth raises histamine load, so treating SIBO often relaxes histamine limits.