What caloric restriction is and the pathways involved
Caloric restriction means reducing energy intake below ad libitum levels, often described in the literature as a sustained reduction without malnutrition, while keeping nutrients adequate. In laboratory animals it reliably extends lifespan and healthspan, an effect attributed to overlapping nutrient-sensing pathways: lower insulin and IGF-1 signaling, increased AMPK activity, dampened mTOR, sirtuin activation, and enhanced autophagy.
Findings vary by species and genetic strain, and the magnitude of any lifespan effect in long-lived mammals is uncertain rather than guaranteed.
How well this translates to humans
Human evidence is more limited and shorter term. Controlled trials such as CALERIE found that moderate restriction improved several cardiometabolic and aging-related markers, but whether it meaningfully extends human lifespan is not established. Sustained restriction also carries real risks, including loss of muscle and bone, low energy availability, and disordered eating in susceptible people.
This is general educational information, not medical advice. Deliberate caloric restriction for longevity is experimental; any such regimen should be planned and monitored with a qualified clinician.