Effects of a Very Low Carbohydrate Diet on Symptoms of Irritable Bowel Syndrome (IBS)

Inclusion Criteria

• Age 18-70 years old, male or female
• Meet Rome II Criteria for IBS-D
• Body mass index > 25 kg/m^2
• Desire to use a very low carbohydrate diet for weight loss
• Score of > 36 on the FBDSI
• Ability to understand consent form
• In stable health by screening history, physical examination performed by a study physician, laboratory tests (normal blood counts, kidney function tests, liver tests, TSH).

Exclusion Criteria

• Age 70 years
• History of inflammatory bowel disease
• History of any gastrointestinal surgery that preceded the onset of IBS symptoms
• Pregnancy or breastfeeding
• FBDSI symptom score of ≤ 36
• Inability to understand consent form
• Diabetes requiring medications (must be controlled with diet and exercise alone).
• Chronic narcotic use for any reason
• Use of serotonin-selective reuptake inhibitors unless patient has been on a stable dose for at least 4 weeks.
• Use of any over-the-counter or prescription weight loss medications.
• Any chronic or unstable diseases (e.g., kidney disease, heart disease, or cancer) that may put the subject at increased risk from the intervention
• Any of the following baseline abnormalities of laboratory tests or physical exam findings:
• Serum creatinine > 1.5 mg/dL in men, > 1.3 mg/dL in women.
• Liver disease (AST or ALT > 2 times the upper limit of normal or total bilirubin > 1.6mg/dL).
• Blood pressure > 160/100 mm Hg.
• Fasting triglycerides > 600 mg/dL.
• Fasting serum low-density lipoprotein (LDL) cholesterol > 190 mg/dL.