I remember a Longevity researcher that was in the public limelight for quite awhile advocating this. I believe he died at around 42 years old. Comparable to Jim Fixx dying so young. Big news at the time years ago. Probably back in the 1980’s.
And I remember watching a documentary about people who severely restricted calories in order to improve longevity. They fully expected to live to 120 or 130. But they were spindly and miserable-looking. They spoke constantly about food and eating. The women all had a layer of very fine fuzz on their faces, one of the body’s responses to starvation.