Anyone have any experience with the calorie restriction diet?

How is a calorie restriction diet different from a weight loss diet?
It’s different in two ways. One is that it has a fundamentally different goal. The goal has nothing to do with weight loss. It’s really about health and longevity. Weight loss is, for many of us, an unfortunate consequence.

Also, people trying to design a weight loss diet might not end up designing one that is capable of promoting longevity. Some diets that are very controversial—like those that are high in protein or, paradoxically, high in fat—may not promote longevity. But it seems like they do promote weight loss, at least in the short term.