Aspiration pneumonia is the leading cause of death among the elderly. Modified-texture foods, i.e., foods with altered consistency, are recommended in order to maintain both normal swallowing and adequate nutrition, which is also expected to reduce aspiration pneumonia, when elderly people are suspected to suffer from disorders of eating and/or swallowing. However, it is reported that overly-restrictive diets have been provided to most residents given modified-texture diets. Furthermore, there is scant empirical evidence of the medical effectiveness of food texture-modification. Little attention has been paid to the effect of the consistency of food substances, as well as the ability of mastication, on general health. Our cross-sectional studies showed that eaters of regular foods have lower incidences of pneumonia and fever, while those eating modified-texture, i.e., softer and finer, foods have higher incidences of pneumonia and fever. In this review, the effects of interventions for prevention of aspiration pneumonia were overviewed then the impact of the consistency of food substances on the health of the elderly and the direction of further research was discussed.