An article on a human study of alternate day fasting is doing the rounds. Studies of intermittent fasting in animals are divided: on the one hand, the beneficial effects on health and longevity look a lot like those produced by straight calorie restriction; on the other hand, there are differences in gene expression and other line items that might be significant. From the article: "Fasting every other day may be a way to live longer as well as lose weight. It may also lower the risk of conditions such as heart disease and cancer, as well as ease symptoms of chronic ailments. Research suggests that calorie restriction, especially alternate-day fasting, has effects beyond those of simple weight loss, and a trial at the University of California has been investigating the long-term effects of fasting. ... After eight weeks of alternate-day fasting we saw that bad cholesterol was down, along with reductions in triglycerides [fat found in blood], blood pressure and heart rates. And since these are all key risk indicators of heart disease, it may not only help people lose weight but also help them decrease their risk of coronary events. ... One mechanism that has been investigated is that fasting triggers a gene whose job is to promote survival by protecting cells during times when food is scarce. Researchers say it helps repair the damage done by free radicals and prevents cells from dying prematurely, as well as lowering inflammation. The gene can also slow the ageing process by reducing the risk of age-related diseases and health threats."