A number of researchers have investigated intermittant fasting as a method of calorie restriction (CR) to obtain health and longevity benefits - no weighty conclusions yet as to whether it's better or worse for the average fellow (or mouse) than simple CR. This paper notes that fasting, as one might expect, causes alterations in sirtuin expression, just like straightforward calorie restriction: "The aim of the present study was to study the role of intermittent fasting (IF) on [diabetic nephropathy (DN)] and studying the expression of Sir2 and p53. At biochemical level, we found that IF causes significant improvement in blood urea nitrogen (BUN), creatinine, albumin and HDL cholesterol, parameters that are associated with the development of DN. Diabetic rats on IF also show significant improvement in onset of hypertension. Interestingly, the expression of Sir2, a NAD dependent histone deacetylase, decreases in diabetic rat kidney and this decrease is overcome by IF." You should already be aware that a better (i.e. smaller) diet can work wonders for type 2 diabetes and related issues - why damage yourself more than you have to?