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The Cedars-Sinai Diet: A Comprehensive Guide for IBS and SIBO Patients

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The Cedars-Sinai Diet: A Comprehensive Guide for IBS and SIBO Patients

Diet indisputably influences human health, so functional medicine healthcare providers always address diet as a primary intervention when helping patients overcome any health concern, especially those pertaining to the gut. There are ten times as many microorganisms within the human gastrointestinal tract as human cells within the body. Diet has a major role in shaping the composition and activity of this microbial population. Many diets have been developed over the years to address dysbiosis-associated digestive complaints and conditions. This article will discuss the Cedars-Sinai diet and how it can help patients find relief from disruptive digestive complaints.


What Is the Cedars-Sinai Diet?

The Cedars-Sinai diet, also known as the low fermentation diet, was originally developed by Dr. Mark Pimentel of Cedars-Sinai Hospital in Los Angeles, California. It is a restrictive eating plan designed to limit fermentable carbohydrates that feed intestinal bacteria and to modify the timing of mealtimes to manage symptoms of small intestinal bacterial overgrowth (SIBO). Through selective eating, the Cedars-Sinai diet acts to starve bacteria out of the gut without starving the patient.

Who Could Benefit from the Cedars-Sinai Diet?

The Cedars-Sinai diet was designed for patients with SIBO. SIBO is the overgrowth of bacteria within the small intestine. When SIBO occurs, the resident bacteria in the small intestine are exposed to easy-to-digest "bacteria food" (fermentable carbohydrates and fiber). As the bacteria digest these foods, in a process called fermentation, excess gases are produced, causing many symptoms associated with SIBO. The predominant symptoms associated with SIBO include abdominal pain, bloating, gas, and abnormal bowel movements.

Patients diagnosed with irritable bowel syndrome (IBS) may also benefit from a low fermentation diet. It is now understood that up to 80% of patients with IBS have an underlying SIBO contributing to their symptoms. This is likely why dietary modifications aimed at reducing fermentable carbohydrates result in symptom improvement in most IBS patients. The low-FODMAP diet, similar to the Cedars-Sinai diet, is commonly recommended for patients with IBS and SIBO and results in symptom improvement for up to 86% of these people.

What Foods Are Allowed on the Cedars-Sinai Diet?

The Cedars-Sinai diet emphasizes the incorporation of foods into the diet that are low in fermentable carbohydrates. Low-fermentable carbohydrates are sugars easily digested in the human gastrointestinal tract. Eating foods with little or no fermentable carbohydrates removes the predominant food source for small intestinal bacteria and limits the amount of gas produced in the digestive tract after eating.

The following are foods patients should be encouraged to eat while following the Cedars-Sinai diet:

  • Refined carbohydrates: white bread (e.g., sourdough, French bread, potato bread), white rice
  • Protein: beef, chicken, eggs, fish, pork
  • Noncruciferous vegetables: peppers, tomatoes, carrots, cucumber, zucchini, squash, eggplant, peas, mushrooms, potatoes, sweet potatoes
  • Fruits, but limit apples, pears, and bananas
  • Lactose-free dairy: if eating cheese, choose a hard, aged cheese that has a much lower lactose content
  • Nuts and seeds
  • Oils
  • Sugars: sucrose (table sugar), glucose

Another critical aspect of the Cedars-Sinai diet is the emphasis on the timing of meals. Avoiding snacking and designating distinct meal times helps promote small intestinal motility and cleansing of the small intestine. Patients should be advised to space meals during the day by 4-5 hours and to eat their last meal at least two hours before bedtime.

What Foods Are Discouraged on the Cedars-Sinai Diet?

Fermentable carbohydrates are limited from the diet because these are more poorly absorbed, pull water into the intestine, and are quickly fermented by bacteria, leading to digestive symptoms of gas, bloating, burping, abdominal pain, and abnormal bowel movements. Short-chain, fermentable carbohydrates are often referred to as FODMAPs, standing for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.

These are the following foods that should be avoided on a Cedars-Sinai diet:

  • Beans and legumes
  • Cruciferous Vegetables: cabbage, brussels sprouts, broccoli, cauliflower, kale
  • Lactose-Containing Dairy: milk, yogurt, and cheeses
  • Whole wheat and multigrain breads
  • Sugars and Sweeteners: sucralose (Splenda™), sorbitol, xylitol
  • Gums: Arabic, xanthan, carrageenan

Functional Medicine Labs That Can Help Individualize the Cedars-Sinai Diet for Patients

Functional medicine providers often order functional medicine tests to better understand the root cause of a patient's digestive symptoms. Functional doctors' and nutritionists' goal is to help their patients regain dietary freedom by identifying and correcting causative factors of digestive dysfunction. Popular labs that aid this process are discussed below.

SIBO Breath Test

SIBO should be suspected in a patient whose digestive symptoms improve by removing fermentable carbohydrates from the diet. SIBO can be confirmed and subtyped by using a diagnostic breath test. Treating SIBO by eradicating bacteria in the small intestine and preventing their regrowth helps patients achieve improved clinical outcomes and food tolerance.

Comprehensive Stool Test

Large intestinal dysbiosis, intestinal infections, digestive enzyme insufficiencies, and intestinal inflammation are also common contributing factors to digestive symptoms and can be diagnosed and monitored with a comprehensive stool test. Reincorporating foods into the diet is often more successful after correcting these factors.

Food Sensitivity Testing

Foods other than fermentable carbohydrates may be the culprit for a patient's digestive symptoms. A food sensitivity panel takes the guesswork out of elimination diets by identifying immune-mediated responses to food proteins. These results can help doctors and patients customize dietary plans for enhanced patient outcomes.

Nutritional Assessment

Given the restrictive nature of the Cedars-Sinai diet, nutritional deficiencies may occur when a patient begins the elimination diet. A nutritional assessment screens for nutrient imbalances and can be ordered before, during, or after the patient completes the Cedars-Sinai diet. When correcting deficiencies with Cedars-Sinai-compliant foods is not possible, a doctor may recommend a dietary supplement to fill nutritional gaps.



The Cedars-Sinai diet is a restrictive dietary meal plan developed by SIBO specialist Dr. Mark Pimentel to help relieve patients from SIBO-related symptoms. By modifying meal timing and the types of carbohydrates in the diet, this low-fermentation diet can be used to treat SIBO and its associated symptoms. Various functional medicine tests can be utilized during a holistic patient evaluation to gather information that helps doctors personalize gut-healing treatment plans.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
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