mm diameter is required for concomitant meal and particle emptying as used herein with respect to the present invention meal and particle emptying shall be deemed to be concomitant if their respective emptying rates are within 20 of one another at a density of 2 g ml the particle size required to achieve concomitant emptying drops to less than about 1 mm in diameter the data depicted in the bar graph of fig1 were obtained by first plotting not shown particle emptying against meal emptying to normalize for day day and dog dog handling of the meal if both emptied at equal rates then the relation would be y x a positive deviation from this relationship indicates that the particles empty faster than the meal while a negative deviation indicates a slower emptying rate for the particles relative to the meal in fig1 the signed sums of the deviations are plotted as a function of particle size for particles of density approximately 1 g ml there is a dramatic change between faster and slower emptying of spheres versus the meal between a particle diameter of 1 6 and 2 4 mm table ii______________________________________signed sum deviation from concomitantemptying with the meals as a function of density signed sum deviation density 1 6 mm 2 4 mm 3 2 mm______________________________________with 1 41 45 18060 ml 2 208 336 211waterwith 1 163 180 ml 0 5 337 water______________________________________ fig2 is a graph which shows the effect of density difference between the spheres.