What is SIBO?
SIBO stands for small intestinal bacterial overgrowth. This means that you have more than the usual number of bacteria living in your small intestine (bowel).
Certain health conditions can make the intestines more likely to have too many bacteria, including:
- Celiac disease.
- Cirrhosis.
- Crohn’s disease.
- Conditions that slow the movement of the intestines (such as gastroparesis, scleroderma, or diabetes-related nerve damage).
- Fatty liver.
- IBS (irritable bowel syndrome).
- Pancreatitis.
- Previous abdominal or intestinal surgery.
- Short bowel syndrome.
What are symptoms of SIBO?
There are many common symptoms of SIBO. Eating certain foods may make these symptoms worse.
- Abdominal distention (visible swelling of the belly)
- Belching or burping
- Bloating (feeling of being too full that can happen after eating)
- Brain fog or difficulty concentrating
- Diarrhea (loose or watery stool 3 or more times a day)
- Excess gas
- Feeling overly full after eating
- Nausea or upset belly
In some cases, SIBO may interfere with the body’s ability to absorb nutrients from food. This can lead to vitamin deficiencies, weight loss, or malnutrition.
Getting started on nutrition therapy for SIBO
SIBO symptoms are often caused by the gas that is made when extra bacteria use up some types of carbohydrates (sugars and starches found in food that your body uses for energy) in your diet, such as certain types of fiber (a substance in food that helps you pass solid waste), starches and/or sugars. Some people with SIBO find that high fat foods can also make their symptoms worse. Changing your diet can help reduce symptoms of SIBO, but diet alone is not able to cure SIBO.
One popular plan to manage SIBO symptoms is called the low-FODMAP diet. On this diet, patients eat less of certain carbohydrates that are likely to make more gas in the intestines or worsen diarrhea. Much of the evidence for the low-FODMAP diet comes from studies in IBS rather than SIBO specifically, and it is best thought of as a way to ease symptoms rather than a proven treatment for overgrowth itself.
FODMAP stands for:
- Fermentable: digestible by bacteria and create gas
- Oligosaccharides: specific types of fiber found in beans, onion, wheat and garlic
- Disaccharide: lactose (or milk sugar) found in milk, yogurt and ice cream
- Monosaccharide: excess fructose, found in honey, mangoes, apples and cherries
- And
- Polyols: natural sugars found in peaches, pears, mushrooms and cauliflower. Sugar substitutes ending in the letters “ol,” like sorbitol and xylitol found in sugar free gums and treats, are also polyols
It can also help to cut back on other fermentable items such as high-fiber foods, prebiotic supplements (for example, inulin), alcohol, and artificial sweeteners like sucralose.
Gluten and dairy are not FODMAPs. A low-FODMAP diet is not gluten-free or dairy-free.
A strict restriction phase is generally temporary. Gradual food reintroduction after about 4 to 6 weeks, ideally with a gastrointestinal dietitian, is recommended. Reintroduction helps identify personal triggers and reduces the risk of unnecessary long-term food restriction and nutrient deficiencies.
Some people with SIBO find that other kinds of carbohydrates or sugary foods can also worsen their symptoms even if they are low-FODMAP. Examples can include rice, cereal, potatoes, large amounts of fruit, table sugar, or desserts. If these types of foods seem to make your symptoms worse, a lower-carb diet may be a more helpful approach than a low-FODMAP diet for managing SIBO symptoms.
Meal spacing
Meal spacing helps your body’s natural cleansing waves in the gut. These waves help to keep bacteria levels lower in the small intestine. It is ideal to wait at least 3 hours between meals or snacks, and not to eat too close to bedtime.
Possible nutrient deficiencies
Having SIBO for a long time can block how your body absorbs nutrients. This can lead to weight loss and deficiencies in vitamin B12 and vitamins A, D and E. Talk with your health care provider to check for these possible shortfalls and whether you need to take a dietary supplement.
Written by
Christine Lothen-Kline, MPH, MCHES, RDN, LDN
Katherine Bennett RD, MPH
Barbara Freedland, MS, RDN
Natalie Rosenbalm (nutrition graduate student)
Reviewed by the DIGID Disorders of the Gut Brain Interaction workgroup, ©2024
Reviewed by
Ali Rezaie, MD, MSc, FRCPC, AGAF,
Medical Director, GI Motility Program
Professor of Medicine, Cedars-Sinai, Los Angeles, CA
Jessica D. Korman, MD
Capital Digestive Care, Washington, DC
AGA Patient Education Advisor
September 2026
Christine Lothen-Kline, MPH, MCHES, RDN, LDN
Katherine Bennett RD, MPH
Barbara Freedland, MS, RDN
Natalie Rosenbalm (nutrition graduate student)
Reviewed by the DIGID Disorders of the Gut Brain Interaction workgroup, ©2024
