In genetically diverse male killifish, reducing calorie or protein intake does not increase lifespan, even though it slows growth and changes body composition.
Mechanism
Synthesis from 1 study
Even when these fish eat less, their bodies don't turn on the systems that fix damage and slow aging. Their mixed genetics means the signal to repair doesn't work the same in every fish, so aging keeps going at the same pace no matter how little they eat.
Most probable mechanism
When food or protein intake drops, the body detects less nutrient availability and normally turns on repair and maintenance systems to extend life. In these fish, those systems do not activate, so aging continues at the same rate even though growth slows and body shape changes.
Nutrient sensing pathways, including insulin/IGF-1 and mTOR signaling, remain active despite reduced dietary intake
Downstream longevity mechanisms such as autophagy, stress resistance, and DNA repair are not upregulated in response to nutrient limitation
Genetic heterogeneity prevents consistent activation of conserved longevity pathways across individuals
Evidence from Studies
Supporting (1)
Community contributions welcome
Neither caloric nor protein restriction increases the male lifespan of outbred short-lived fish
Contradicting (0)
Community contributions welcome
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.