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What is the most effective SIBO diet?

Since releasing my first book in the Fast Tract Digestion book series on Heartburn which linked chronic acid reflux to Small Intestinal Bacterial Overgrowth (SIBO), I have received many inquiries about using the Fast Tract Diet to treat other SIBO-related conditions such as IBS (update: Fast Tract Digestion IBS / Fast Tract Diet App now available) and celiac disease. To answer this question, I am going to review several other diets that may be applicable to treating SIBO along with the Fast Tract Diet.

What is SIBO?

In healthy people, the small intestine contains low levels of friendly bacteria such as Lactobacillus acidophilus, especially in the upper part of the small intestine where our own critical digestion takes place. SIBO involves the invasion of the small intestine with much greater numbers of bacteria from the large intestine.

The official definition of SIBO is “the presence of an abnormally high number of bacteria (more than 100,000 bacteria per milliliter) in the upper part of the small intestine”. At this level, the normally harmless bacteria that live in our gut can become harmful. They produce toxins, enzymes, and intestinal gases, including hydrogen, methane, and carbon dioxide that can disrupt digestion, cause intense physical discomfort and even damage the small intestine.

The symptoms of SIBO include abdominal pain or cramps, diarrhea, constipation, gas, bloating, acid reflux, flatulence, nausea, dehydration, and fatigue. More severe symptoms related to SIBO can include weight loss and “failure to thrive,” steatorrhea (the body’s failure to digest fats), anemia, bleeding or bruising, night blindness, bone pain and fractures, leaky gut syndrome, autoimmune reactions, and among others.

There is an abundance of scientific research linking SIBO to a growing number of digestive (and even systemic) conditions. The list continues to grow but already includes:

  • Irritable bowel syndrome (IBS)
  • Gastroesophageal reflux disease (GERD)
  • Celiac disease
  • Crohn’s disease
  • Diverticulitis
  • Fibromyalgia
  • Chronic fatigue syndrome
  • Asthma
  • Rosacea
  • Interstitial cystitis
  • Autoimmune disorders
  • Cystic fibrosis

SIBO has many underlying causes, but here some that stand out:

  • Slowed motility (how well food moves through the intestine)
  • Low stomach acidity
  • Immune deficiency
  • Antibiotic usage
  • Pancreatic insufficiency
  • Low ileocecal valve pressure (separates the large from the small intestine)
  • Damage to intestinal villi (finger-like projections for absorbing nutrients)
  • Food poisoning or gastroenteritis
  • Carbohydrate malabsorption (key for dietary control)

Though each of these issues could increase your chances of having SIBO and should be identified and addressed where possible, the driving force behind SIBO is always poorly absorbed carbohydrates. That’s because gut bacteria consume mostly carbs for energy.

For this reason, the best way to control SIBO is to deny gut bacteria the fuel they need to overrun the small intestine by limiting the consumption of certain carbohydrates. The worst offenders are the hard-to-digest carbohydrates including:

  • Lactose
  • Fructose
  • Resistant starch
  • Fiber
  • Sugar alcohols

The Fast Tract Diet considers these hard-to-digest carbs as having “Fermentation Potential” (FP). Limiting FP, as opposed to limiting overall carbs, is the secret of lasting symptom relief. Fast Tract Digestion uses an FP point system to control hard-to-digest carbs.

SIBO Diets

Back to the question, “Can the Fast Tract Diet be used to treat other SIBO-related conditions?” The answer is yes, although specific conditions may have additional requirements. For instance, any diet for celiac disease would require all gluten (even small amounts) to be removed. With this in mind, the Fast Tract Diet is specifically designed to treat SIBO by limiting the carbohydrates listed above that drive bacterial overgrowth.

Other diets have also been used to treat SIBO-related conditions. These include:

  • Paleo Diet
  • Elemental Diet
  • Specific Carbohydrate Diet (GAPS Diet)
  • Low Starch Diet
  • Low Carb Diet
  • FODMAP approach

These diets all limit carbohydrate malabsorption to varying degrees. Let’s take a closer look at each.

The Paleo Diet

Paleo diet experts make a rational case that eating as our ancestors ate is healthier.  The reason is, our bodies evolved in balance with the foods that were available before we learned to cultivate grains. You hear different opinions on the details as no one knows for sure what paleolithic humans ate or what their diets were like locally. More fruits would be available in tropical areas. People near lakes, rivers, or the ocean relied more heavily on aquatic foods. Hunting was a common thread as supported by fossil records. Foods tended to be uncooked and many foods we tend to dismiss in the modern Western world (i.e. insects) were likely part of the caveman diet.

I have gained a general view of Paleo diet foods from reading some great books including, The Paleo Solution, by Rob Wolf, The Primal Blueprint by Mark Sisson, and Perfect Health Diet by Paul snd Shu-Ching Jaminet. Other excellent sources of information on Paleo eating include Danny Alber’s Blog, Primal North (for real deal, hardcore Paleo – not live at this time) and the website, Paleohacks.com. I also attended the two most recent Ancestral Health Symposia (you can see my ASH2013 presentation here).

My takeaway message is this.

“Modern Paleo diets are based on food types that were available and consumed during our evolution.”


  • Fish, meats; including organs, fowl, and eggs
  • Green vegetables, fruits, nuts, seeds, and herbs
  • Insects


  • Cassava, Sweet Potatoes, Yams, Wild rice, Taro

Off Limits:

  • Most grains (though Mark’s plan allows some wild rice and Paul Jaminet’s Perfect Health Diet allows more starch including white rice)
  • Beans and pulses
  • Dairy and foods containing dairy
  • PUFA-containing oils except olive and coconut oil
  • Processed foods containing sugars and trans fats, nitrates, and other additives.

Clearly, this diet is a big step in the right direction for gut health! The Paleo diet removes or limits many difficult-to-digest carbohydrates that are tied to SIBO. Let’s take a closer look at Paleo diet foods to see if some might give Mark’s caveman, Grok, a little indigestion.

Removing most grains, beans, pulses, dairy, and processed sugars should make a big improvement in reducing SIBO-related symptoms. But, I would advise caution on some of the other “acceptable” food choices when experiencing symptoms.

Some white rice (basmati and Uncle Ben’s for example) are known to contain significant amounts of resistant starch and should be limited. Wild rice likely contains significant amounts of resistant starch, though I can’t confirm this as a fact without a GI  value and I don’t believe wild rice has been tested.

I would recommend jasmine rice with a known Fermentation Potential (FP) value of zero. But, don’t eat too much if you have high blood sugar or insulin resistance.

How about fruit? Many fruits contain high amounts of fructose. Because fructose is a single sugar, it requires no digestion, but it’s absorbed slowly into the bloodstream. This makes it more available for excessive fermentation in the gut. There are many studies liking fructose consumption to gut problems, especially IBS symptoms. Apples, pears, cherries, grapes, plums, are examples of fruits containing a lot of fructose.

Another fruit that can create issues is bananas. Bananas have a lot of resistant starch, especially under-ripe bananas. Resistant starch, like all difficult to digest carbs, hangs around providing gas-producing bacteria fuel.

What about dairy? Dairy is restricted on the Paleo diet because it wasn’t an available food source throughout our evolution. For gut health, the major issue is lactose. I agree that high lactose dairy such as milk and ice cream (there is lactose-free ice cream available) should be avoided. I don’t see the benefit of excluding a number of other low-lactose or fermented dairy foods discussed in my book. I personally can’t imagine life without them.

Of particular interest are tubers and root vegetables, which are allowed on most Paleo diets. These include potatoes, sweet potatoes, parsnips, celery root, carrots, beets, daikon, yams, and turnip. Some contain significant amounts of resistant starch and should be limited.  See my recommendations at the end of the article for safe choices.

The Elemental Diet

The Elemental diet consists of foods that are essentially “predigested.” The foods contain fatty acids rather than fats, amino acids rather than proteins, and glucose instead of carbohydrates. The diet formula also includes water and micronutrients — vitamins and minerals.

Elemental diet products such as Nestle’s Vivonex can be delivered orally or enterally (by tube). Elemental diets are designed to ensure full absorption and have been used to treat a broad range of digestive conditions including Crohn’s and celiac disease, lactose intolerance, malabsorption, diarrhea, constipation, diabetes, cystic fibrosis, abdominal distention, and short bowel syndrome.

Note that all of these conditions have a connection to SIBO. Some limitations of the elemental diet approach include high cost, unappealing (predigested) food products, and the need for medical supervision.

The Specific Carbohydrate Diet

The book Breaking the Vicious Cycle by Elaine Gottschall describes her experiences with Drs. Sidney and Merrill Haas, who successfully treated celiac disease with a diet that allowed only specific sugars and starches. The Specific Carbohydrate Diet limits disaccharide or double sugars as well as grains and starch but allows simple sugars like glucose.

In general, this dietary approach is on the right track, but some carbohydrates potentially contributing to SIBO-related illness are not limited. For example, honey is used extensively in the recipes even though honey has just as much fructose as table sugar (sucrose is made of equal parts glucose and fructose). And the diet allows a large variety of fruits and fruit juices that also contain large quantities of fructose, which is now recognized as a major contributor to the development of SIBO.

Finally, the SCD does not allow any grains or foods containing starch. It identifies amylose starch as easy to digest and amylopectin starch as difficult to digest. In other words, the diet suggests that amylopectin is more likely to cause problems. But, the reverse is actually true.

Uncle Ben’s rice, for example, contains both amylose and amylopectin starch and it has a high FP / symptom potential, while sushi rice which contains no amylose (only amylopectin) has a very low FP / symptom potential.

Note: The GAPS Diet (Gut and Psychology Syndrome) created by Dr. Natasha Campbell-McBride is based on the Specific Carbohydrate Diet but also includes detoxification and supplementation.

The Low Starch Diet

Carol Sinclair popularized the Low Starch Diet in her book The IBS Low-Starch Diet. Sinclair discovered that reducing starch in her diet improved her IBS symptoms. She also collaborated with Dr. Alan Ebringer, a professor of immunology at Kings College in London, UK, who found that the diet could improve painful symptoms of ankylosing spondylitis (AS).

Dr. Ebringer has made the connection between the autoimmune disease AS, intestinal overgrowth of the bacterium Klebsiella pneumonia, and controlling the bacteria’s growth through a low-starch diet. Sinclair’s book limits all starches as well as sucrose, lactose, and maltose.

Like the Specific Carbohydrate Diet, the Low Starch Diet unnecessarily limits all starch, yet does not limit fructose, thus limiting the effectiveness in treating SIBO.

The Low Carb Diet

The book Protein Power by Drs. Mike and Mary Dan Eades documented how low-carb dieting helped people with heartburn. Clinical studies have also shown that strict (ketogenic) low-carb dieting can improve IBS and GERD, two conditions associated with SIBO [i] Despite impressive results (as documented in my first book, Heartburn Cured), not everyone gets complete symptom relief from a low carb diet.

One possible explanation for the variations in results is that the low-carb diets don’t specifically restrict fiber (though limiting high carb foods also limits fiber) or sugar alcohols — known contributors to SIBO-related digestive illness. Another reason might be a simple failure to stick with the diet.

The FODMAP Approach

Susan Shepherd and Peter Gibson developed the FODMAP Diet at Monash University in Victoria, Australia.[ii] The acronym FODMAP represents four classes of fermentable sugars/sugar alcohols:  Fermentable Oligo-, Di-, and Monosaccharides, And Polyols.[iii] The FODMAP approach limits fructose, fructans, lactose, galactans, and sugar alcohols.

While the approach makes sense and has helped people with IBS and other SIBO-related conditions, the FODMAP diet includes sucrose in many low FODMAP recipes and does not restrict resistant starch and fiber found in sweet potatoes, certain kinds of rice, corn, gluten-free pasta, gluten-free bread, cereals and bananas for example.

Sucrose, because it’s half fructose, and resistant starch are both significant contributors to malabsorption and excessive fermentation. The FODMAP diet actually calls for adding more resistant starch. As a recent article on the diet stated, “Part of dietary counseling is to ensure continuing adequate intake of resistant starch.”[iv]

The Fast Tract Diet – New Way to Treat SIBO

The Fast Tract Diet limits all difficult-to-digest carbohydrates including:

  • Fructose
  • Lactose
  • Fiber
  • Resistant starch
  • Sugar alcohols

And the diet uses a special method called Fermentation Potential (FP) to calculate the potential for any food containing carbohydrates to cause symptoms. Mathematically derived FP values (they are listed in 15-16 tables in the books but can also be calculated) for each food help identify and restrict difficult-to-digest carbohydrates without having to know what specific carb types are in each food. So you don’t need the help of a medical professional or dietician.

Fast Tract Digestion IBSUnlike a strict low-carb diet, the Fast Tract Diet limits fiber but can include some higher-carb foods as long as they don’t contain too many difficult-to-digest carbohydrates. For instance, sushi rice, which contains little resistant starch, is acceptable, but basmati rice, which contains more resistant starch, is not.

The Fast Tract Digestion book series also explains and addresses the other underlying problems listed above that can contribute to SIBO.

In addition to the overall recommendations in the books, here are 5 recommendations that are missing in some of the other diets to control SIBO and limit symptoms:

Limit high amylose rices

High amylose kinds of rice are high FP. There are lower amylose kinds of rice available that are safe for gut issues.

Limit high amylose tubers or root vegetables

High amylose tubers and root vegetables are also high FP. There are other low FP choices such as parsnips, and several potato varieties available.

Limit sucrose and high fructose fruits

Sucrose and high fructose fruits are high FP. These can be substituted with many Low FP fruits such as strawberries, cantaloupe, and others. Consume other (high FP) fruits, such as apples and bananas as small wedges or single slices. Switch out high FP sucrose with Low FP sweeteners such as dextrose, erythritol (the one safe sugar alcohol), etc.

Limit dairy with excess lactose (high FP)

Acceptable alternatives include cream and a variety of fermented dairy products.

Limit fiber and sugar alcohols (except erythritol)

They are poorly digested and fermentable potentially driving SIBO and symptoms.

Note: Some low FP starchy vegetables, while gut-friendly, are higher in carbs. Use your judgment and limit your overall carb levels to avoid metabolic complications from high blood sugar, such as metabolic syndrome, diabetes, obesity, and cardiovascular health.

How to get started with the Fast Tract Diet for SIBO

Fast Tract Diet App for Gut Health1. Read the Fast Tract Digestion IBS book

2. Get the Fast Tract Diet Mobile App for Android or iPhone/iPad

3. Take the On-demand SIBO Masterclasses (2 classes and Q&A sessions for the price of 1)

Need Individualized help for SIBO and/or other digestive health issues?  Call for consultation at 844-495-1151 US or contact via this online form

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[i]Yancy WS Jr, Provenzale D, Westman EC. Improvement of gastroesophageal reflux disease after initiation of a low-carbohydrate diet: five brief cased reports. Altern Ther health med. 2001. Nov-Dec; 7(6):120,116-119. Austin GL, Thiny MT, Westman EC, Yancy WS Jr, Shaheen NJ. A very low-carbohydrate diet improves gastroesophageal reflux and its symptoms. Dig Dis Sci. 2006 Aug;51(8):1307-12. Austin GL, Dalton CB, Hu Y, Morris CB, Hankins J, Weinland SR, Westman EC, Yancy WS Jr, Drossman DA. A very low-carbohydrate diet improves symptoms and quality of life in diarrhea-predominant irritable bowel syndrome. Clin Gastroenterol Hepatol. 2009 Jun;7(6):706-708.

[ii] Shepherd S, Gibson P. Fructose malabsorption and symptoms of irritable bowel syndrome: guidelines for effective dietary management.  J Am Diet Assoc. 2006 Oct ;106 (10):1631-9.

[iii] Gibson, P, Shepherd, S. Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach.  J Gastroenterol Hepatol. 2010 Feb ;25 (2):252-8  20136989.

[iv] Peter R Gibson, Susan J Shepherd. Evidence-based Dietary Management of Functional Gastrointestinal Symptoms: The FODMAP Approach. J Gastroenterol Hepatol. 2010;25(2):252-258.