Effect of the physical state of a food on subsequent intake in human subjects.

The effect of the physical state of food on further intake was studied. Human subjects were served two experimental foods at lunchtime 1 week apart. In a first experiment, the two-food meals had the same caloric content, weight, volume, composition and temperature but differed only in their physical form (solid or liquid). As compared to the solid meal, the 24-h total caloric intake following the liquid food was higher. This difference could be attributed to cognitive cues from the form of food or to the lack of masticatory movements while ingesting the liquid meal. The last hypothesis was tested in a second experiment. "In which the test-meals appeared absolutely identical to the senses and were composed of a liquid and a solid item; however, the major part of calories was either in the liquid or in the solid part. When most of the calories had to be drunk, the total subsequent caloric intake was higher than when the most of the calories had to be eaten. It seems that calories ingested in a liquid form are not well taken in account and could induce a subsequent overconsumption, at least until satiety was conditioned to the fluid.