Along with the rapid growth of population aging, most of the developed countries as well as Japan are faced with the serious social issue about care needs for elderly. This article describes the needs of diet in super aged society by introducing some results from the field research with a special focus on food diversity and health of the elderly people. Taking a variety of foods is reported to have positive affects on health status and even longevity. However, food diversity is reported to decline with age. Authors revealed that the elderly who ate less varied foods were more disabled, depressed and had lower Quality of Life (QOL) and lower chewing ability. Eating alone is also a important factor to be addressed for the mental well-being of the elderly. The possibility of the social innovation for healthy aging is discussed through "food diversity" and "shared meal".