The effects of a standardized mixed meal, a self-selected meal and a sham meal on heart rate, arterial pressure, cardiac output, total systemic resistance and echocardiographic indexes of left ventricular performance were examined in normal volunteers. Supine heart rate and cardiac output increased after the meals (p less than 0.07 to 0.001), but not after the sham meal. Supine diastolic blood pressure and total systemic resistance decreased after the meals but not after the sham meal (p less than 0.05 to 0.001). Ejection fraction and mean velocity of circumferential fiber shortening increased after the standard meal (p less than 0.01) and tended to increase after the self-selected meal, but did not increase after the sham meal. Meals of normal size may induce splanchnic vasodilation and a decrease in total systemic resistance. Ingestion of food also significantly affects heart rate, blood pressure, cardiac output and echocardiographic indexes of left ventricular performance. Patients should not eat during short-term evaluation of cardiovascular interventions because the cardiovascular effects of a meal may compromise interpretation of the cardiovascular effects of the primary intervention. The hemodynamic effects of food may also interact with the effects of cardiovascular disease processes.