The purpose of this study is to determine whether a specific diet may help children with irritable bowel syndrome.

Many children experience stomach pain or discomfort at some point during their lives. Some children have belly discomfort frequently while others rarely have this problem. There have been very few studies to test treatments for recurrent stomach discomfort in children. Recently, studies in adults with recurrent stomach discomfort suggest that diet changes may help. Currently, we do not know if these same diets will work in children with the same problem.

In this study, two different diets will be provided (delivered) for two days with at least 5 days in between each provided diet. The child's symptoms will be recorded over the two days of each diet. Children will be asked to capture samples of their breath during the last day of the each two day delivered diet. Stool samples will also be collected.

Inclusion Criteria:

Must include all of the following:

1. Children between the ages of 7-17 years;
2. Meet the criteria for IBS based on the Questionnaire on Pediatric Gastrointestinal Symptoms Rome III Version, including pain/discomfort a minimum of twice per week;
3. Negative physician evaluation for an organic etiology of the pain within the past year

Exclusion Criteria:

Will include any of the following:

1. Diabetes or other disease process requiring specialized dietary management;
2. Malnutrition or obesity (BMI >95%);
3. Inability to eat by mouth;
4. Antibiotic or medicinal probiotic usage within the past 3 months (excluding yogurt);
5. Neuromodulator (e.g. amitriptyline) usage within the past 3 months
6. Start of, or change in gastrointestinal medication (e.g. laxative) dose that may cause or ameliorate abdominal symptoms within the past month