What is the SIBO Diet?

The Small Intestinal Bacterial Overgrowth (SIBO) diet is designed to manage the symptoms of SIBO, a condition where excessive bacteria grow in the small intestine. It is also called The Bi-Phasic SIBO Diet. This diet focuses on reducing fermentable carbohydrates, which can feed the bacteria and cause symptoms like bloating, gas, diarrhea, or constipation. The goal of the SIBO diet is to support digestive health, minimize symptoms, and complement medical treatments like antibiotics or herbal antimicrobials.

Here, you will learn how to decide if the SIBO Diet is right for you, how to get started on a SIBO diet, what to eat, what not to eat, and what to expect from this well-recognized approach to SIBO.

Understanding the SIBO Diet for You

Commonly, it incorporates elements of the Low-FODMAP diet, which limits foods high in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, and may include other modifications tailored to individual needs.

The SIBO diet greatly reduces foods that feed the excess bacteria in the small intestine. Reducing the foods the bacteria need, in turn reduces the amount of bacteria, and that is exactly what helps alleviate uncomfortable symptoms like bloating, gas, and irregular bowel movements. This approach is less about carbohydrate restriction and more about choosing the right types of carbohydrates to limit bacterial fermentation in the gut.

At its core, the diet emphasizes avoiding foods that are high in fermentable sugars and fibers, as these can worsen bacterial overgrowth. Commonly restricted items include certain fruits, vegetables, dairy, and grains, and the specifics will vary depending on individual tolerance. The goal is to find a balance that nourishes the body while reducing bacterial activity.

Because everyone’s gut responds differently, the SIBO diet is personalized using a few phases, starting with more restrictive phases and gradually reintroducing foods to test tolerance. By adopting this approach, many people find relief from symptoms and support their overall gut health in tandem with medical treatments.

Different Types of SIBO Diets

While the SIBO Diet being covered here is one specific method, there are also previous versions of diets to help SIBO that have led up to what is now known as The SIBO Diet. It is great to know about these in order to avoid confusion and to put them in context in relation to The SIBO Diet. The SIBO Diet is laser focused on SIBO, and so is a better choice to start with. The diets that follow each seek to limit bacterial overgrowth, but they are less comprehensive than The SIBO Diet. For some people, one of these diets can become their maintenance diet after going through the initial SIBO Diet phases to really knock down the bacterial populations.

• • Low-FODMAP Diet: This diet focuses on reducing fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), which are short-chain carbohydrates that are poorly absorbed in the gut. It is often used as a starting point for managing SIBO symptoms, and it is the backbone of the Bi-Phasic SIBO Diet. The low-FODMAP diet commonly includes foods like lean meats, fish, eggs, certain low-FODMAP vegetables, and lactose-free dairy.
  • Specific Carbohydrate Diet (SCD): This diet eliminates complex carbohydrates and starches that are difficult to digest, leaving only simple carbohydrates that are more easily absorbed by the body. Like all these versions, it aims to starve bacteria by limiting the carbohydrates they ferment. On this diet, permitted foods include fresh fruits, non-starchy vegetables, unprocessed meats, and homemade fermented yogurt.
  • Elemental Diet: This is a very unique short-term diet for severe cases of SIBO. It is an entirely liquid diet consisting of pre-digested nutrients (amino acids, simple carbohydrates, and fats) that are easily absorbed in the small intestine. As such, the diet bypasses digestion and deprives bacteria of fermentable material in that way.
  • Bi-Phasic Low SIBO Diet: The diet being detailed in this guide combines aspects of the Low-FODMAP and Specific Carbohydrate Diets into a phased approach. Phase 1 focuses on reducing bacterial overgrowth and inflammation through tighter food restrictions. Phase 2 gradually reintroduces more foods while maintaining symptom control.
  • Gut and Psychology Syndrome (GAPS) Diet: GAPS is like the SCD but emphasizes gut healing through nutrient-dense, easily digestible foods and fermented foods. It is used for SIBO and other digestive issues to restore gut health over time. It is also a popular approach for children with autism.

Unless SIBO is so severe that a period on an elemental diet with a professional is needed, the Bi-Phasic SIBO Diet is the most targeted choice when dealing with SIBO. Implementing that diet will be detailed in the rest of this guide.

Potential Health Benefits

The SIBO diet is most thought of for its namesake condition SIBO. But it is also used during other gastrointestinal problems such as inflammatory bowel syndrome (IBS), gastro-esophageal reflux disease (GERD), functional dyspepsia, and chronic bloating and gas. In all of these situations, what the SIBO diet contributes is starving the overgrown bacteria to reduce their populations.

The Bi-Phasic SIBO Diet: A Case for Success in Managing SIBO

The Bi-Phasic SIBO Diet has shown to be effective for many people in managing SIBO, and it has been positively reported by both clinicians and patients alike. While scientific studies directly validating its efficacy may still be limited, anecdotal evidence and clinical practice suggest significant improvements in symptoms for those following the protocol. Here is an overview of how the Bi-Phasic SIBO Diet helps many with SIBO:

Effective Symptom Relief

Anecdotal evidence and reports from practitioners who specialize in SIBO treatment suggest that the Bi-Phasic SIBO Diet offers significant symptom relief for many patients. By limiting fermentable carbohydrates, the diet reduces the fuel available for bacteria to ferment, leading to reduced gas, bloating, and abdominal discomfort. These benefits are critical for patients who have been battling SIBO symptoms that hinder their quality of life  1^✓.

The Role of Phases in Restoring Gut Health

The Bi-Phasic approach is unique in that it separates the treatment into two distinct phases. Phase 1 restricts high-FODMAP foods and focuses on reducing bacterial overgrowth and inflammation. This phase is particularly effective for immediate symptom reduction. In Phase 2, foods are gradually reintroduced, allowing individuals to identify personal triggers and re-establish a balanced and sustainable diet. This phased approach has been praised for its ability to both provide short-term relief and foster long-term gut health    2^✓.

Promoting Gut Healing and Improving Motility

In addition to reducing bacterial overgrowth, the Bi-Phasic Diet includes gut-healing nutrients that support the integrity of the gut lining and improve motility. Many patients report a reduction in symptoms related to gut motility issues, such as early satiety, nausea, and constipation. By targeting both the bacterial imbalance and gut function, the Bi-Phasic Diet addresses multiple aspects of digestive health, making it a comprehensive approach  3^✓.

Personalized Approach to Identifying Triggers

The structured reintroduction of foods in Phase 2 allows for the identification of specific dietary triggers. This is crucial for people with SIBO who may also experience sensitivities to certain foods that exacerbate their symptoms. The gradual reintroduction process ensures that patients can personalize their diet and avoid future flare-ups. Clinicians often note that this aspect of the Bi-Phasic Diet contributes to long-term symptom management and helps prevent relapse  1^✓.

Supporting Gut Microbiota Balance

By focusing on reducing small intestinal bacterial overgrowth, the Bi-Phasic Diet creates an environment in which healthy bacteria can thrive. The reduction in bacterial fermentation can improve the overall gut microbiome, contributing to better digestion and reduced inflammation. This positive shift in gut health is often reflected in improved energy levels, less bloating, and a better overall sense of well-being   2^✓.

The Bi-Phasic SIBO Diet, despite limited formal research, has proven to be an effective tool for many patients dealing with SIBO. Through its structured approach of food elimination and gradual reintroduction, it offers symptom relief, promotes gut healing, and supports long-term gut health. While individual responses to dietary changes can vary, this diet has helped numerous patients regain control over their digestive health and improve their quality of life.

How the Bi-Phasic SIBO Diet May Help Manage IBS Symptoms

While direct scientific research specifically examining the Bi-Phasic SIBO Diet’s impact on IBS is limited, several studies and clinical observations suggest that dietary interventions targeting SIBO can alleviate gastrointestinal symptoms commonly associated with IBS.

A narrative literature review highlights the potential benefits of dietary interventions in managing SIBO-related symptoms, which overlap with those of IBS, such as bloating and abdominal discomfort  4^✓. Further, most people with IBS actually have SIBO ( 5^✓,    6^✓.) Therefore, the Bi-Phasic Diet’s structured approach to reducing fermentable carbohydrates and identifying individual food triggers may offer a beneficial strategy for managing IBS symptoms.

SIBO Diet for GERD?

Direct scientific research specifically examining the SIBO Diet and GERD is still in its infancy. However, it is useful to consider an important connection that suggests the SIBO diet may alleviate GERD symptoms.

SIBO may play a role in the development or exacerbation of GERD. Excessive bacteria in the small intestine can result in excessive gas, which can increase intra-abdominal pressure. This increased pressure can cause stomach acid to reflux into the esophagus, leading to GERD symptoms. Since the Bi-Phasic Diet helps reduce bacterial overgrowth, it may potentially alleviate GERD symptoms.

Functional Dyspepsia Has Many Connections To SIBO

Functional dyspepsia simply refers to upper abdominal discomfort or pain that isn’t otherwise diagnosable as a specific disorder. There is no identifiable biochemical or structural cause. It is a diagnosis of exclusion. Symptoms can include the following:

• • A feeling of fullness during or after eating (early satiety).
  • Upper abdominal burning or pain.
  • Bloating or stomach pressure.
  • Nausea and occasional vomiting.
  • Burping or acid reflux.

The Bi-Phasic SIBO Diet, while primarily designed for managing Small Intestinal Bacterial Overgrowth (SIBO), can also help alleviate symptoms of functional dyspepsia (FD). This is because both conditions often involve similar digestive symptoms and may share overlapping mechanisms, such as impaired motility or gut sensitivity. Here’s how the Bi-Phasic SIBO Diet may be beneficial for functional dyspepsia:

Reduces Gas Production and Bloating

Functional dyspepsia is often associated with bloating and a sense of fullness, which can be exacerbated by gas-producing bacteria in the gut. The Bi-Phasic Diet restricts fermentable carbohydrates that bacteria feed on, reducing gas production and easing pressure in the upper abdomen   1^✓. 

Supports Gut Motility

Delayed gastric emptying or poor gut motility is a common factor in functional dyspepsia. By minimizing foods that slow digestion or promote bacterial overgrowth, the Bi-Phasic Diet can help restore more normal motility, potentially reducing symptoms like fullness and nausea   7^✓. 

Reduces Gut Inflammation

Some cases of functional dyspepsia involve low-grade inflammation of the stomach lining or intestines. The anti-inflammatory properties of the Bi-Phasic Diet, which emphasizes nutrient-dense, gut-soothing foods, may help calm irritation in the digestive tract  8^✓. 

Addresses Food Intolerances

People with functional dyspepsia often have food sensitivities or intolerances that trigger symptoms. The structured, phased approach of the Bi-Phasic Diet allows for the identification of problematic foods through gradual reintroduction, helping to personalize the diet for symptom relief 1^✓. 

Balances Gut Microbiota

An imbalance in gut bacteria (dysbiosis) can contribute to both SIBO and functional dyspepsia. By reducing bacterial overgrowth in the small intestine, the diet can create a healthier gut environment, which may alleviate symptoms like bloating, gas, and abdominal discomfort (  8^✓, 9^✓, 10^✓, 11^✓,)

Improves Food Tolerance

Functional dyspepsia often causes early satiety or discomfort with eating. The Bi-Phasic Diet emphasizes easily digestible foods in its initial phase, reducing the digestive burden and making meals more tolerable   7^✓. 

While the Bi-Phasic SIBO Diet can help functional dyspepsia symptoms, it is not a cure. Combining dietary changes with other treatments, such as medications, psychological therapies, or stress management, is often necessary for optimal results.

Foods To Include and Avoid in Each Phase of The SIBO Diet

Phase 1: Reduce and Heal (6-12 weeks)

The objective with this phase is to reduce bacterial overgrowth and alleviate symptoms by completely restricting aggravating foods. Phase one occurs in two parts: the elimination phase and the gut healing phase.

Always choose the highest quality food you can find. This means organic and grass-fed or free-range meats and eggs, fish from non-polluted waters, non-GMO and organic soy, and organic or no-spray fruits and vegetables. Select heirloom varieties of produce whenever they are available as these contain the highest nutritional content.

Elimination Phase (2-6 weeks)

The key is to eat plenty of the unlimited foods throughout the day in order to intentionally keep nutrition up, while at the same time being very strict with the avoided foods and the quantity limits to quickly reduce bacteria.

In this phase, a restricted Low-FODMAP diet is followed. High-FODMAP foods such as garlic, onions, wheat, certain fruits, and dairy products are avoided. While there is a focus on certain low-FODMAP foods like leafy greens, berries, meat, fish, eggs, and limited gluten-free grains.

Elimination Phase Includes the Following Foods:

Proteins (Fresh & Simple):

• • Organic Meat: Chicken, turkey, beef, lamb, duck, quail, venison, goat
  • Clean Seafood: wild salmon, shrimp, Sultan Ibrahim, sardines, red snapper, local tuna, clams, sherry, mackerel, squid, mussels, king fish, blue crab, octopus, lady fish

Organic Eggs

• • Plant-Based: Firm tofu (up to 100g), Tempeh (up to 100g)

Unlimited Low-FODMAP Vegetables (Cooked or Raw):

• • Lettuces: all loose leaf and head lettuces. Get the highest nutrition from Rocket and other heirloom lettuces.
  • Vegetables: bamboo shoots, red pepper, cucumber, eggplant/aubergine, olives in brine or olive oil, green onion (green part only), tomato, yellow squash
  • Leafy Greens: pak choi, chard, choy sum, kales. Get the highest nutrition from heirloom varieties like Curly Scarlet.
  • Sprouts: alfalfa, broccoli, ginger, mung up to 7cm, radish, snow pea, sunflower

2 servings-per-meal Limited Low-FODMAP Vegetables (Cooked or Raw):

• • Asparagus 1 spear
  • Artichoke hearts 25 g
  • Beet root 40 g
  • Broccoli 45 g
  • Brussels sprouts 2 sprouts
  • Cabbages 35 g
  • Carrots (orange) 120 g
  • Celery 40 g
  • Celery root 55 g
  • Courgette or Yellow squash 85 g
  • Fennel bulb 50 g
  • Green beans 50 g
  • Leek (green leaf) 25 g
  • Nori seaweed 2 g
  • Peas (green) 30 g
  • Sugar snap or Snow peas 15 g
  • Spinach (baby) 45 g
  • Spinach (mature) 60 g
  • Squash (spaghetti) 50 g
  • Zucchini (yellow or green) 85 g

1 serving-per-meal Limited Low-FODMAP Starchy Vegetables (Cooked or Raw):

• • Carrot (yellow, purple, red, white) 30 g
  • Squash (pumpkin, kabocha, kent, butternut) 50 g

2 servings-per-day Fruit:

• • Lemons
  • Limes

Limited Gluten-Free Whole Grains: (soaked and cooked)

• • Buckwheat 85 g
  • Hulled millet 120 g
  • Quinoa (red or white) 120 g
  • Rice (basmati or jasmine) 120 g
  • Kelp or konjac noodles 75 g

Soups:

• • Homemade broths comprised of allowed proteins and vegetables

Beverages:

• • Organic coffee 1 cup/day
  • Milks: almond, coconut, hemp, rice (no added sugar, gums, thickeners) 1 cup/day
  • Teas: black, herbal
  • Water: filtered

Sweeteners:

• • 100% pure stevia (Make sure it has no inulin added.)

1 serving-per-meal Nuts & Seeds:

• • Almonds 10 each (14 g) or Almond flour/meal 14 g
  • Almond butter 16 g
  • Chia seeds 12 g
  • Coconut (flour/shredded) 20 g
  • Coconut cream 30 g
  • Coconut milk (no thickeners or gums) 60 g
  • Flaxseed 3.5 g
  • Hazelnuts 7 g
  • Hemp seeds 20 g
  • Macadamias 25 g
  • Mixed nuts 18 g
  • Pecans 10 g
  • Pine nuts 10 g
  • Pumpkin seeds 20 g
  • Sesame seeds 9 g
  • Sunflower seeds 5 g
  • Walnuts 10 halves (14 g)

Condiments, Herbs, Spices:

• • Chives or garlic chives
  • Chili 28g limit
  • Mayonnaise (sugarless)
  • Mustard (without garlic)
  • Tabasco
  • Herbs & Spices fresh or dried

Fats and Oils:

• • avocado, chili-infused olive oil, coconut, flax (low lignan), garlic infused olive oil, ghee, MCT, olive

Gut Healing Phase (4-6 weeks)

In this second half of phase I, the goal is to start repairing the gut lining while continuing to control bacteria. The key is to gradually reintroduce some low-FODMAP foods that were previously restricted in order to diversify your diet.

At this point, gut-healing nutrients are added as supplements and fermented foods. These are added very slowly and individually based on tolerance.

The Gut Healing Phase Includes the Following Foods:

Proteins (Fresh & Simple):

Organic Meat: Same as in Elimination.

Clean Seafood: Same as in Elimination.

Organic Eggs

Plant-Based: Same as in Elimination, plus black-eyed peas (up to 65 g cooked), lima beans (up to 70 g cooked), mung beans (up to 65 g cooked), lentils (up to 60 g cooked).

Unlimited Low-FODMAP Vegetables (Cooked or Raw):

Lettuces: Same as in Elimination.

Vegetables: Same as in Elimination, plus parsnip.

Leafy Greens: Same as in Elimination.

Sprouts: Same as in Elimination.

2 servings-per-meal Limited Low-FODMAP Vegetables (Cooked or Raw):

• • Asparagus 3 spears
  • Artichoke hearts 25 g
  • Beet root 40 g
  • Broccoli 45 g
  • Brussels sprouts 50 g
  • Cabbages 35 g
  • Carrots (orange) 120 g
  • Celery 40 g
  • Celery root 55 g
  • Courgette or Yellow squash 110 g
  • Fennel bulb 50 g
  • Green beans 50 g
  • Leek 175 g
  • Nori seaweed 2 g
  • Peas (green) 30 g
  • Sugar snap or Snow peas 15 g
  • Spinach 150 g
  • Squash (spaghetti) 50 g
  • Zucchini (yellow or green) 110 g

1 serving-per-meal Limited Low-FODMAP Starchy Vegetables (Cooked or Raw):

• • Carrot (yellow, purple, red, white) 30 g
  • Potato (peeled) 80 g
  • Squash (pumpkin, kabocha, kent, butternut) 120 g

2 servings-per-day Fruit:

• • Avocado 55 g
  • Banana 60 g
  • Berries (all varieties) 75 g
  • Carambola/Star fruit 95 g
  • Cherries 15 g
  • Citrus fruit 135 g
  • Grapes 55 g
  • Honeydew melon 40 g
  • Kiwi 75 g
  • Lemons
  • Limes
  • Lychee 45 g
  • Papaya 35 g
  • Passion fruit 19 g
  • Pineapple 55 g
  • Pomegranate 45 g
  • Rhubarb 55 g
  • Rock melon/Cantaloupe 50 g

Limited Gluten-Free Whole Grains:

• • Same as in Elimination plus Arrowroot flour 16 g.

Soups:

• • Same as in Elimination.

Beverages:

• • Same as in Elimination, plus…
  • Clear spirits 30 ml twice per week
  • Soy milk (organic, unsweetened, no gums or thickeners) 45 ml

Sweeteners:

• • Same as in Elimination, plus…
  • Dextrose
  • Glucose
  • Honey (organic, clear) 42 g

1 serving-per-meal Nuts & Seeds:

1. • Almonds 10 each (14 g) or Almond flour/meal 14 g
   • Almond butter 16 g
   • Chia seeds 24 g
   • Coconut (flour/shredded) 20 g
   • Coconut cream 30 g
   • Coconut milk (no thickeners or gums) 60 g
   • Flaxseed 7 g
   • Hazelnuts 14 g
   • Hemp seeds 20 g
   • Macadamias 25 g
   • Mixed nuts 18 g
   • Pecans 18 g
   • Pine nuts 10 g
   • Pumpkin seeds 20 g
   • Sesame seeds 9 g
   • Sunflower seeds 5 g
   • Walnuts 10 halves (14 g)

Condiments, Herbs, Spices:

• • Same as in Elimination plus…
  • Coconut aminos
  • Fish sauce
  • Miso
  • Tamari

Fats and Oils:

• • Same as in Elimination plus organic grass-fed butter.