The Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA. * Correspondence: Dr S. B. Roberts, Energy Metabolism Laboratory, USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington St. , Boston, MA 02111. tel: (617) 556-3237. fax: (617) 556-3344

Abstract: Inadequate energy intake is common in older individuals and is probably the major cause of unexplained weight loss. This summary highlights recent studies on possible causes of negative energy balance in older individuals suggesting that aging is associated with a significant impairment in the regulation of food intake that inhibits appropriate short-term and long-term compensation for normal fluctuations in energy intake. The combination of a reduced ability to regulate energy intake, decreased dietary variety, and disadvantageous social factors such as functional limitations, social isolation and depression, increases the risk of negative energy balance leading to weight loss in older individuals.

Key words: elderly, energy intake, anorexia, body composition regulation of energy intake in old age