The SIBO-Specific Diet: A Complete Low-Fermentation Food Guide for Bacterial Overgrowth

Understanding SIBO and Why Food Matters

Small Intestinal Bacterial Overgrowth (SIBO) occurs when bacteria that normally belong in the large intestine migrate into the small intestine and overgrow. Unlike normal gut bacteria, these bacteria ferment poorly absorbed carbohydrates in the small intestine itself, producing gas, bloating, and abdominal pain. The SIBO-Specific Diet combines the Specific Carbohydrate Diet (SCD) and Low-FODMAP principles to limit foods that feed these bacteria while antimicrobial treatment eliminates them.

• Fermentable carbohydrates feed SIBO bacteria and worsen gas, bloating, and cramping
• Lower-fermentation foods are better tolerated and less likely to feed SIBO
• This diet is temporary---typically used for four to eight weeks during active treatment
• Adequate caloric intake is critical; underfeeding while restricting foods slows healing
• Cooking vegetables generally makes them easier to tolerate than eating them raw

This Is a Temporary Healing Diet, Not a Lifestyle

Better-Tolerated Vegetables (Lower Fermentation)

These vegetables are generally well tolerated on the SIBO diet in moderate portions. Cooked vegetables are preferred over raw, as cooking breaks down fiber and makes digestion easier.

• Arugula, bamboo shoots, bok choy (1 cup)
• Broccoli (½ cup cooked), cabbage (1 cup cooked)
• Carrot, celery root, chives, cucumber
• Eggplant, endive, fennel
• Green beans (10 pods), leafy greens: lettuce, collard, chard, kale, spinach (in moderation)
• Olives, bell peppers or sweet peppers
• Radish, rutabaga, scallions (green part only)
• Snow peas (5 pods), summer squash, zucchini (¾ cup)
• Fresh tomato (in moderation)
• Cooking tip: Steaming or roasting vegetables breaks down fiber and makes them significantly easier to digest. Avoid raw vegetables when possible during the initial treatment phase.

Vegetables to Limit or Avoid (Higher Fermentation)

These vegetables contain higher amounts of fermentable carbohydrates and are best limited or avoided during active SIBO treatment. You can reintroduce them gradually once SIBO is treated.

• Artichoke, asparagus, butternut squash (more than ½ cup)
• Beet (more than two slices)
• Brussels sprouts, savoy cabbage (more than ¾ cup)
• Leek, parsnip
• Peas (more than ¼ cup), spinach (more than 15 leaves)
• Chili pepper (more than 28 grams)
• Sun-dried tomato, tomato soup, tomato juice
• High-fructose fruits and juices
• Onion and garlic: These are among the highest FODMAP foods and should be strictly avoided. They are potent SIBO triggers.
• Cruciferous vegetables: Cauliflower and large amounts of broccoli should be limited. Small amounts of steamed broccoli may be tolerated.

Proteins, Fats, and Other Foods

These categories are generally well tolerated on the SIBO diet. Focus on fresh, whole foods without additives.

• Proteins: All fresh meat, poultry, eggs, and fish are allowed. Choose unprocessed options without added sugars or fillers.
• Fats: Butter, ghee, olive oil, coconut oil, and avocado oil are all permitted. Healthy fats support nutrient absorption and reduce inflammation.
• Dairy: Hard cheeses are lower in lactose and generally tolerated well. Fresh lactose-free dairy products are acceptable. Avoid milk, cream, and soft cheeses.
• Nuts and seeds: Almond, walnut, macadamia, and sunflower seeds in small amounts are tolerated. Avoid cashews and pistachios, which are higher in fermentable carbohydrates.
• Grains to avoid: All grains are avoided on the SIBO diet, including gluten-containing and gluten-free varieties. Reintroduce rice and other gluten-free grains later during recovery.
• Sweeteners: Use only small amounts of pure maple syrup or honey. Avoid sugar alcohols (sorbitol, mannitol, xylitol) and artificial sweeteners, which feed SIBO bacteria.

Foods to Strictly Avoid During Treatment

A Sample Day of SIBO-Specific Eating

Here is what a typical day might look like while following the SIBO diet:

• Breakfast: Scrambled eggs with butter, plain white rice, and steamed spinach
• Morning snack: Small handful of almonds with carrots
• Lunch: Grilled chicken breast with roasted broccoli and olive oil, salt, and herbs
• Afternoon snack: Sliced cucumber with salt
• Dinner: Baked salmon with roasted zucchini and summer squash, olive oil, and fresh herbs
• Key principles: Adequate protein at each meal, healthy fats for satiety, cooked vegetables for better tolerance, no raw vegetables, no sugary foods, no fermented foods during active treatment

Maintaining Adequate Nutrition During Treatment

The SIBO diet is restrictive, but you must still eat enough to support your body and immune function. Underfeeding slows healing.

• Aim for at least 1,800 to 2,200 calories daily depending on your size and activity level
• Include protein at each meal (palm-sized portion is a good visual guide)
• Use healthy fats liberally to increase calorie density and nutrient absorption
• Eat until satisfied---do not restrict portions artificially
• If you feel weak, fatigued, or are losing weight rapidly, you are likely undereating. Increase portions, especially of proteins and fats.
• Work with your provider if you struggle to maintain weight or energy during the diet

After SIBO Treatment: The Reintroduction Protocol

Once your provider confirms SIBO is resolved (typically with a breath test), you will slowly reintroduce restricted foods. This gradual process helps you identify which foods your system can tolerate and rebuilds your beneficial microbiome.

• Reintroduction typically begins two to four weeks after finishing antimicrobial treatment
• Start with lower-FODMAP vegetables like garlic and onions (small amounts) to test tolerance
• Add one new food category every three to five days and monitor for symptom return
• If symptoms return, pull back that food and try again in one to two weeks
• Reintroduce fermentable vegetables and complex carbohydrates in a phased, gradual manner
• Work with your provider---the reintroduction protocol is individualized based on your response

Frequently Asked Questions

The SIBO Diet Works Best With Professional Guidance

While this guide provides the framework for the SIBO-Specific Diet, success requires professional guidance. Your provider will monitor your progress, adjust the protocol based on your response, and guide your reintroduction. SIBO is treatable, and most people recover fully with the right combination of diet, antimicrobials, and professional support.