We conducted a study of model foods for use with microwave heating, in which the dielectric properties that are so important when microwave heating is used could be adjusted and fine-tuned. Agar gel was used as the base in the model foods, and sucrose and sodium chloride were used to adjust the dielectric properties. It was found that the addition of sucrose primarily changed the dielectric constant, whereas the addition of sodium chloride primarily changed the dielectric loss factor. Based on this discovery, we proposed a procedure for determining the concentrations of sucrose and sodium chloride to be added when applying a certain dielectric constant and dielectric loss factor. We created model foods in which the additions of sucrose and sodium chloride were made to mimic a gratin sauce in consistency, and conducted a heating experiment using microwaves. We found good agreement between the temperature increases in the model food and those in the real food. (C) 2004 Elsevier Ltd. All rights reserved.