Within- and Between-Subject Variation in Dietary Intake of Fermentable Oligo-, Di-, Monosaccharides, and Polyols Among Patients with Irritable Bowel Syndrome.

There is more variation between subjects than within subjects regarding FODMAP intake. To correctly estimate an individual's absolute intake of FODMAPs, the number of days of diet records required exceeds what is reasonable for a participant to accomplish. However, ranking individuals into quartiles of FODMAP consumption can be achieved using a 4-d food record. This trial was registered at www.clinicaltrials.gov as NCT02107625 and NCT01252550.