Abstract
This paper reviews age related changes in body fat, fat-free body mass, and the subcomponents of FFM including protein, mineral, and body water. It gives an overview of common methods and their limitations in the elderly and reviews the effects of physical activity on body composition in middle-aged and older individuals. Surprisingly little information is available on this important topic in men and women >80 years of age. Although research to date has described a number of qualitative trends with aging and shown the correlations between changes in fat and FFM with disease risk, quantification of rate of change has proven difficult. This is partly because changes in the aging body affect the indicators of body composition, leading to estimation errors, and because few long-term longitudinal studies have been completed. The increasing awareness of the important relationships among health, nutrition, and body composition, and the profound change in population demographics projected for the next 25 to 50 years, has focused attention on this problem and will undoubtedly stimulate additional research in this area.