Disposable soma theory

The disposable soma theory, proposed by Thomas Kirkwood in 1977, says your body has to budget its limited energy. It splits resources between maintaining the body (somatic upkeep) and reproduction. Because evolution rewards reproductive success, the body invests just enough in repair to survive the hazards it is likely to face, no more. That leaves some damage unrepaired, and it builds up as aging. The theory is still influential in the evolutionary biology of aging. And it underlies modern thinking on caloric restriction and life's trade-offs.

Last reviewed: June 22, 2026

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