Appetite, hunger, and satiety in the elderly.

Food intake declines with age and the elderly frequently report a decrease in appetite. Social and physical factors as well as decreased energy expenditure may be part of the explanation for the decreased food intake; however, it is possible that changes in hunger mechanisms are also involved, but more studies similar to those conducted on thirst are needed. The consumption of a varied diet depends in part on sensory-specific satiety, that is, the decrease in the pleasantness of a food as it is consumed. We have shown that sensory-specific satiety changes with age such that it was absent in individuals over the age of 65 and this could be part of the explanation of why the elderly consume more monotonous diets. Additional basic studies on how aging affects the controls of food intake will suggest ways to improve the nutritional status of the elderly.