The world population is aging rapidly. Japan has the oldest population in the world, with 28% of the current population aged 65 y or older. Maintaining good nutrition is important for preventing age-related deterioration in health. Physical activity levels, energy intake, and weight tend to decrease with age. Decreased food intake increases the risk of undernutrition due to the inadequate intake of essential nutrients. The proportion of the older population that is malnourished ranges from 1% to 5% among independent older adults living in the community, and increases to 30% to 50% among residents of care institutions. Among older adults, the risk of death increases with increasing leanness. In Japan, the government pays considerable attention to the prevention of adverse health effects related to obesity among young and middle-aged adults, although the adverse health effects related to undernutrition and being underweight among older adults have been overlooked. In addition to providing nutrients, eating has important psychological and social benefits. Therefore, there is a need to pay attention to the diet and nutritional needs of older adults in Japan in order to promote and maintain their physical and mental health.
Keywords: Japan; food intake; life expectancy; malnutrition; undernutrition.