BioMed Central provides a good explanation of recent research into the underlying genetic and regulatory mechanisms of calorie restriction. "Caloric restriction and genetic manipulations that extend lifespan typically protect cells from death. We propose that one way calorie restriction extends lifespan is by increasing SIRT1 expression, thereby promoting the long-term survival of irreplaceable cells." Researchers are clearly very excited about progress made in the last year, and hope that this will lead to a "totally new class of drug that stimulates the body's own defenses and combats diseases of aging." Companies like BioMarker and Elixir are already working in this area.