Taste and appetite regulation in the elderly.

The Belgian mathematician Quetelet (1835) in his treatise on human development wrote ‘Man is born, grows up and dies according to laws which have never been properly investigated either as a whole or in the mode of their mutual reactions’, thereby reinforcing our awareness that ageing is an inevitable and natural process in life but that this process is not well-understood. Quetelet (1 835) made observations on the laws of development and aging by examining crosssectional data sets, a methodology which is employed frequently in modem times. Over the last 150 years considerable insight into developmental processes across the lifespan has been afforded by both cross-sectional and longitudinal studies. Large national surveys such as the Baltimore Longitudinal Study of Aging (US Department of Health and Human Services, 1984) demonstrate profound changes in lifestyle, health, nutrition and economics of the population as a function of ageing, and permit a window on this, our most certain and natural fate.