This is Cornaro’s central claim and the one Zarzo and others label an “Immortality Diet”: that holding to a spare fixed ration preserves health and carries a person to a vigorous extreme old age, as he says it did for him. It is classified as a testimonial because it generalises from a single self-reported life history. It is recorded as untested rather than refuted: an individual anecdote, however often repeated, is not a controlled demonstration, and there is no comparison group, no measured endpoint beyond the single reported lifespan, and no control for the many other determinants of how long Cornaro lived. The strength of the claim is further weakened by the fact that the reported lifespan itself is unreliable, since Cornaro overstated his age.