> First, how can eating less than required to maintain mass be healthy? Define healthy? They may lose muscle mass / strength but still get sick less and live l

> First, how can eating less than required to maintain mass be healthy? Define healthy? They may lose muscle mass / strength but still get sick less and live longer. In my mind it makes some sense that slowing down your metabolism moderately could make your body "last" longer... but this is just me trying to make sense of things and I'm far from an expert.