What effect does aging have on body weight?
Aging is associated with changes in body composition that may be influenced by the endocrine milieu and can have important endocrine/metabolic consequences. In general, body weight increases with advancing age until about age 60 years; thereafter, it stabilizes and then declines after age 65 to 70 years. This may be attributed to improved survival of adults without obesity and/or a “die off” effect in the heaviest individuals during middle age. However, the reduction in body weight in older adults, whether intentional or unintentional, appears to be associated with an increase in mortality, morbidity, and disability. Indeed, there is a well-described obesity paradox in older adults, wherein higher body mass index (BMI) is associated with lower overall mortality, and weight loss is associated with greater mortality compared with weight stability. The causes for this are not clear, but it is possible that any sustained weight loss may, in fact, be unintentional, as intentional weight loss is difficult to maintain. Weight loss, in the face of illness or disease raises cytokine levels and may predispose to a disproportionate loss of weight as lean mass (muscle mass). This weight loss exacerbates age-related sarcopenia (loss of muscle mass and strength) and leads to a catabolic state. It is also possible that the apparent obesity paradox of aging is related to the time of onset of obesity in older adults, with obesity beginning at a young age or in middle-age being associated with untoward consequences, and obesity beginning at an older age being less dangerous. Interventions in these two potentially heterogeneous groups might also be expected to produce different health-related outcomes, but these have not yet been studied.
Body Composition Changes with Aging