Bullshit. Caloric restriction beyond the point of a normal energy balance has never been proven to increase longevity in humans, or any higher primate in the wild.

The experiments showing longevity benefits from extreme caloric restriction have been conducted with small animals living in safe lab environments where they are protected from injuries and infectious diseases. Out in the real world, sarcopenia is a real killer. Elderly people need adequate (but not excessive) caloric intake in order to maintain muscle strength and prevent falls.

Temporary fasting for a few days likely has some benefits, at least for younger people with good lean muscle mass. But that's different from what people usually refer to as caloric restriction.