Hypothesis

Beta-hydroxybutyrate (βHB) extends lifespan in C. elegans by inhibiting HDACs and activating DAF-16/FOXO and SKN-1/Nrf pathways [4]. Rather than merely repairing damage, this response may reflect an evolutionarily conserved program that couples ketone signaling to a senescence‑promoting state when external nutrients are scarce, thereby limiting individual reproduction and freeing resources for kin. If aging is a selected trait [see seed idea], then interventions that chronically elevate βHB could be fighting a programmed mechanism, leading to compensatory costs that have not been captured in short‑term assays.

Testable predictions

1. Food‑dependence of lifespan extension – In C. elegans, the lifespan‑extending effect of βHB (or HDAC inhibition) will be significant only under low‑bacterial‑food conditions; under high‑food conditions the same treatment will either fail to extend life or will reduce fecundity and increase susceptibility to oxidative stress.

2. Kin‑benefit read‑out – Populations exposed to chronic βHB will show increased expression of specific SASP factors (e.g., IL‑6, IGF‑BP homologs) that enhance dauer formation or stress resistance in neighboring larvae, measurable as improved survival of progeny when resources are limited.

3. Compensatory damage accumulation – Long‑term βHB treatment in mammals will lead to detectable accumulation of a specific class of molecular damage (e.g., lipid peroxidation products or mitochondrial DNA deletions) that is tolerated due to enhanced Nrf2 activity, but whose removal (via senolytics or DNA repair activators) will further extend lifespan beyond that achieved by βHB alone.

4. Genetic epistasis – Knock‑down of the HDAC isoforms targeted by βHB (e.g., hda‑1/hda‑2) will phenocopy the lifespan extension only when the FOXO‑like transcription factor DAF‑16 is intact; loss of DAF‑16 will abolish the benefit and reveal a hidden cost in reduced brood size.

Experimental outline

• C. elegans assays: Synchronized L1 larvae raised on low (0.5 mg/mL) vs high (5 mg/mL) E. coli OP50 with or without 10 mM βHB; measure median lifespan, brood size, dauer formation, and SASP‑like reporter activity (e.g., GFP‑tagged hsp‑16.2).
• Mammalian pilot: Mice fed a ketogenic diet producing sustained βHB (~2‑3 mM) for 6 months; assess markers of DNA damage (γH2AX), lipid peroxidation (4‑HNE), and SASP cytokines in liver and adipose tissue; compare to pair‑fed controls and to mice receiving a senolytic cocktail.
• Genetic tests: Use CRISPR‑generated hda‑1/hda‑2 knock‑outs and daf‑16 mutants to evaluate epistatic interactions.

Falsifiability

If βHB’s pro‑longevity effect is independent of food level, does not alter SASP‑related kin‑benefit markers, and does not reveal hidden damage accumulation or trade‑offs in fecundity, then the hypothesis that βHB engages an evolved senescence program would be falsified. Conversely, observing food‑dependent lifespan effects, kin‑oriented secretory changes, and compensatory damage would support the idea that ketone signaling taps a selected aging mechanism rather than merely repairing stochastic damage.