The older population is the single largest demographic group at disproportionate risk of inadequate diet and malnutrition. Ageing is associated with a decline in a number of physiological functions that can impact nutritional status, including reduced lean body mass and a resultant decrease in basal metabolic rate, decreased gastric secretion of digestive juices and changes in the oral cavity, sensory function deficits, changes in fluid and electrolyte regulation and chronic illness. Medication, hospitalization and other social determinants also can contribute to nutritional inadequacy. The nutritional status of older people is an important determinant of quality of life, morbidity and mortality. This review critically examines the factors that contribute to the development of poor nutritional status in older people and considers the consequences of malnutrition.