This cross-sectional study evaluates the relations between the water load test in childhood functional gastrointestinal disorders with food intake and nutritional status. Patients with functional dyspepsia required a lower maximum water intake to produce fullness (n = 11, median = 380 mL) than patients with irritable bowel syndrome (n = 10, median = 695 mL) or functional abdominal pain (n = 10, median = 670 mL) (P < 0.05). Among patients who ingested ≤560 mL (n = 17) or >560 mL (n = 14) in the water load test, there was no relation between the maximum drinking capacity and food intake, body mass index, or height.