What is the main mechanism behind the claim? I've heard it may have to do with the fact that catabolic conditions correlate to a longer lifepan. With that said,

What is the main mechanism behind the claim? I've heard it may have to do with the fact that catabolic conditions correlate to a longer lifepan. With that said, I'm sure there are people who (at least occasionally) want to be in an anabolic state, so I wonder how to balance those conflicting goals. E.g., can you get similar effects by creating a catabolic window for a few months every year?