A universal eating monitor has been developed that permits covert continuous weighing of a subject's plate or other food reservoir by means of a concealed electronic balance. By coupling the device with a digital computer, it is possible to record precisely the amount consumed every 3 s throughout a single-course meal consisting of a relatively homogeneous mixture of foods. The monitor have been used to compare total intake, meal duration, initial rate of intake, and deceleration of intake in human subjects ingesting either a solid or liquid version of the same food after 3 or 6 h without food. It was found that the liquid form was eaten faster than the solid form, but that total amounts consumed in each form were not significantly different. These results suggest that when the rate of consumption is controlled by the physical consistency of the food, the amount eaten is not determined by the rate of consumption alone. Further studied are necessary to determine the relative roles of visual cues and interoceptive signals on quantity eaten.