Understanding the genetic and biochemical mechanisms of metabolism is much akin to organising a nest of paper clips - find a loose one and keep tugging to see what it's attached to. From Newswise, the latest on research into the roots of calorie restriction and its effects on longevity: "Mice, rats, worms, flies, and yeast all live longer on a low-calorie diet, which also seems to protect mammals against cancer and other aging-related diseases. A gene called SIR2 is thought to control this process. ... Triggered by low salt, heat, or extreme calorie restriction, a yeast 'master longevity regulator' called PNC1 stimulated SIR2 activity. This new work [demonstrates] that PNC1 regulates the whole SIR2 family of genes, suggesting that a human PNC1 gene might protect against diseases of aging such as cancer, heart disease and diabetes."