To obtain information about the integrated response of the cardiovascular system to food, cardiac output and regional blood flow (superior mesenteric artery, renal artery and calf blood flow) were measured in 14 normal young healthy subjects after an overnight fast and following a standard 800-kcal meal. Results were compared with 8 subjects who remained fasted throughout the study. Cardiac output increased from a mean (SEM) fasting value of 4.8 (0.3) 1/min to a peak after 30min of 6.1 (0.5) 1/min (p