Those following the ongoing investigations of calorie restriction biochemistry, metabolism and potential gains in healthy longevity may find this interesting: "sirtuins directly controlled the two-member class of enzymes called AceCSs (for acetyl-CoA synthetases) ... This reversible process transformed the AceCSs into a form that allows the body to utilize the small fatty acid called acetate. ... Acetate can be very important in animals as an energy source ... In humans, acetate can be obtained from the diet and as a by product of other metabolic processes. However, it is believed that we don't generally rely on it heavily as an energy source. ... it's not clear what role acetate metabolism may play in the little-understood sirtuin molecular system that seems to confer so many advantages, but a connection to diabetes and aging does exist. Studies from the 1960s and early 1990s showed that diabetics and aged individuals exhibit a decreased ability to utilize acetate."