Can you have olive oil on a SIBO prep diet? A definitive guide

October 6, 2025 •

4 min read

Strict adherence to the preparatory diet is crucial for obtaining accurate Small Intestinal Bacterial Overgrowth (SIBO) breath test results. Given the restrictive nature of this diet, a frequent question that arises is: Can you have olive oil on a SIBO prep diet?

Quick Summary

Olive oil is generally permitted on a SIBO prep diet because it is a fat and lacks fermentable carbohydrates. It can provide calories and flavor to the restricted diet but must be used in moderation to ensure accurate test results.

Key Points

Olive oil is safe: Pure, unflavored olive oil is generally permitted on a SIBO prep diet because it is a fat and not a fermentable carbohydrate.
Moderation is recommended: While allowed, use olive oil sparingly. Excessive fat intake can slow gastric emptying and potentially impact test timing.
Avoid infused oils: Steer clear of flavored or infused olive oils that may contain hidden ingredients like garlic or herbs, which are not allowed on the prep diet.
Fats provide energy: During a highly restrictive prep diet, healthy fats like olive oil can help provide necessary calories and make bland food more palatable.
Prep diet is crucial for accuracy: The purpose of the strict prep diet, including the careful selection of fats, is to ensure the breath test results are accurate and not skewed by food fermentation.
Always follow provider guidance: SIBO prep protocols can vary, so always confirm the specific list of allowed foods and restrictions with your healthcare provider.

What is the SIBO prep diet and why is it necessary?

The SIBO prep diet is a temporary, highly restrictive eating plan followed for 24 to 48 hours before a breath test. Its primary purpose is to starve the bacteria in your small intestine, minimizing any gas production from food fermentation that could interfere with the test results. The test measures hydrogen and methane gases produced by bacteria after you ingest a lactulose or glucose solution, so it's vital that no other dietary sources of fermentation are present. Failure to follow the diet can lead to false positives, inaccurate readings, and an incorrect diagnosis.

The diet typically restricts all high-fiber foods, whole grains, nuts, seeds, and most fruits and vegetables. This leaves a very limited list of allowed foods: plain proteins (like meat, fish, and eggs), plain steamed white rice, clear meat broth, and certain fats and oils.

The role of olive oil in the SIBO prep diet

Unlike fermentable carbohydrates, which are the main culprits in feeding bacteria, olive oil is a fat that does not contain fermentable sugars or carbs. This makes it a suitable source of calories and flavor during the restrictive prep period. Its high content of monounsaturated fats means it is not a direct food source for the bacteria being measured in the breath test, thereby not compromising the accuracy of your results.

Purity and quality of olive oil

When using olive oil for the SIBO prep diet, it's crucial to select a pure, unflavored variety. Infused or flavored olive oils often contain added ingredients like garlic or herbs, which are high in fermentable FODMAPs and would be strictly prohibited. Stick to extra virgin or regular olive oil with no additives to maintain compliance with the diet.

Moderation is key

While olive oil is a safe option, moderation is still important. Consuming excessive amounts of any fat, including olive oil, can slow down gastric emptying. This delay could potentially affect the timing of the breath test readings, leading to less reliable results. Most protocols recommend using small amounts for cooking or as a light dressing on allowed foods.

Comparison of fats during SIBO prep

Different types of fats have different compositions and are not all treated equally during the SIBO prep period. The table below helps clarify which fats are generally acceptable and which should be avoided. Consult your healthcare provider's specific instructions, as protocols can vary slightly.


Feature	Permitted Fats (e.g., Olive Oil)	Restricted Fats (e.g., Some Dairy)
Carbohydrate Content	Very low to zero fermentable carbs.	Can contain lactose (a fermentable carb).
Effect on Fermentation	Does not feed intestinal bacteria, thus maintaining test accuracy.	Can provide a food source for bacteria, potentially causing false readings.
Digestibility	Composed of fatty acids, easily absorbed without bacterial fermentation.	High-FODMAP fats (e.g., butter with milk solids) are restricted.
Flavoring	Only pure, unflavored oil is acceptable.	Flavored oils, especially garlic-infused, are prohibited.
Source	Plant-based oil (avocado, coconut also OK).	Dairy fats (milk, soft cheese, most butters) contain lactose.
Moderation	Recommended to use in small amounts.	Not applicable, as restricted fats should be avoided entirely.

Beyond olive oil: Other allowed foods on the prep diet

To make the restrictive diet more tolerable, it's helpful to know what other foods are typically allowed. This helps you plan meals that are compliant and as satisfying as possible.

Allowed Food List:

Proteins: Plain, baked, or broiled meat, fish, seafood, and poultry (uncured, unbrined).
Eggs: Scrambled, hard-boiled, or fried with a small amount of an allowed oil.
Carbohydrates: Plain, steamed white rice (jasmine or basmati). Some protocols may allow plain white bread or sourdough.
Broth: Clear meat broth made from just meat and water, with no added vegetables, bone, or cartilage.
Fats and Oils: Coconut oil, vegetable oil, butter, and lard are often permitted alongside olive oil.
Seasonings: Only salt and pepper.
Beverages: Plain water, weak black coffee, or weak black tea without sweeteners or cream.

Sample meal ideas using olive oil

Following the prep diet can be challenging, but incorporating an allowed fat like olive oil can add variety. Here are some meal ideas:

Breakfast: Scrambled eggs cooked with a small amount of olive oil, seasoned with salt and pepper.
Lunch: Baked chicken breast drizzled with olive oil, served with plain steamed white rice.
Dinner: Baked salmon seasoned with salt and pepper, lightly cooked in olive oil.
Snack: Hard-boiled eggs with a light drizzle of olive oil, salt, and pepper.

Conclusion

In conclusion, pure olive oil is an acceptable and safe fat to include in a SIBO prep diet. Because it lacks fermentable carbohydrates, it will not interfere with the accuracy of your breath test results. However, it is essential to use pure, unflavored olive oil in moderation and to follow all other dietary guidelines provided by your healthcare provider. By doing so, you can ensure a successful and reliable SIBO breath test, putting you on the right path toward an effective treatment plan.

For additional authoritative information on SIBO and preparatory diets, consult the SIBO Center website: https://sibocenter.com/

Frequently Asked Questions

Olive oil is primarily a fat and contains no fermentable carbohydrates, unlike many other food sources. Since the SIBO breath test measures gas from carbohydrate fermentation, pure fat does not interfere with the results.

No, you should only use pure, unflavored olive oil. Infused or flavored oils often contain prohibited ingredients like garlic, which can contain fermentable compounds that could skew your test results.

The key is moderation. Use a small amount of olive oil for cooking or as a light drizzle. Excessive fat intake can slow digestion, which may affect the timing of the breath test readings.

Besides olive oil, other simple fats often permitted include coconut oil, vegetable oil, butter, and lard. Always refer to your specific testing facility's guidelines.

Consuming excessive fat or a flavored oil with fermentable ingredients could potentially cause false-positive results or unreliable test timing. If this happens, inform your healthcare provider, who may recommend rescheduling the test to ensure accuracy.

Olive oil is included in the prep diet to provide a safe calorie source, not to treat SIBO symptoms. The goal of the diet is to prepare for the test, not to address the underlying condition.

You can use a small amount of olive oil to cook plain, baked, or broiled meats, fish, or eggs. It can also be drizzled over plain steamed white rice.