This second of three discussions about ageing biology and diseases continues at the level of the organism, examining the relationship among body composition, late life and diseases. One view of significant age-related mass loss in humans suggests that anabolic failure is associated with various precipitating factors that may share anorexia in common. Lean mass decline with even partial anorexia should alert clinicians to monitor patients for emergence of otherwise subclinical disease. Weight or mass loss and clinical disease also may be independent, thus creating an interwoven and complex view. Recent data from the Portuguese water dog genetics model suggest that heritable factors play a role in end of life body metrics and some histological changes, and that some metric and histological changes are themselves inter-related. While widespread inflammation and hyperplasia were less frequent than expected, there exists nonetheless a disease relationship to the growth hormone (GH)-insulin-like growth factor (IGF-1)-insulin axis that requires further exploration. Oxidative metabolism and apoptosis are reviewed briefly as examples at the cellular level that may be reflected in gross ageing phenotypes, further underscoring the complex nature of many late-life diseases.