years lose its effect, or even worse, be detrimental to our overall health and thus reduce not extend our life-expectancy and/or life-qualityFrom rodent studies we already know that a life-long alternate-day feeding protocol increases lifespan in the absence of any caloric reduction (Goodrick. 1990; Mattson. 2000). Evidence that similar beneficial effects, at least as far as mortality from chronic disease is concerned, would occur in human beings comes from a 2007 study by Varaday and Hellerstein (Varaday. 2007), who do yet remark that (as I already pointed out) "more research is required to establish definitively the consequences of ADF [alternate day fasting]".The circadian clock hypothesis A finding from alternative day fasting studies that may be of paramount importance in view of the "quality of life"-aspect, is the increase in brain-derived neurotropic factor (BDNF) that has been observed in animal studies. BDNF is involved in brain development and plasticity and its (intermittent) fasting-induced elevation could explain the neuroprotective effect of respective feeding patterns (Duran. 2001). In a review of the literature, Fory and Miskin do yet remark that (Froy. 2010)[...] BDNF could not be [directly] linked to the neuro-protective effects in the brain of calorically restricted rats, but increased levels of another neurotrophic factor, glial cell line-derived factor (GDNF), were correlated with neuro-protection of a calorically restricted primate model of Parkinson's disease. Interestingly, BDNF is also a component of the hypothalamic melanocortin pathway that controls food intake and body weight in adult mice, and it has been implicated in the regulation of energy metabolism. After all, the scientists believe that IF exhibits part or even all of its effects by (re-)setting clock genes, a hypothesis which despite having its merits would yet lead us into theoretic considerations with little merit to our "intermittent thoughts" on the real-world outcomes of intermittent fasting, which is why I will, at this point, skip forward to the results of a 1999 study into the relation of adipose tissue size and reductions thereof to longevity.Is it not about eating less, but just about getting leaner?Image 4: When we are talking about the benefits of losing body fat, this obviously does not imply you have to get in Phil Heath Mr. Olympia '11 shape to live longer (photo bodybuilding.com)In the introductory paragraphs of this installment of the Intermittent Thoughts on Intermittent Fasting series I somewhat ridiculed the idea of changing one's whole life to get "ripped and buffed", now, after revisiting some of the studies and observing the close correlation of improvements in metabolic health markers, reductions in body fat and consequent life-extending effects of (intermittent) fasting, the central question of Nir Barzilai's and Gaurav Gupta's 1999 paper Revisiting the Role Fat Mass in the Life Extension Induced by Calorie Restriction seems by no means far fetched: What if ain't inflammation and insulin resistance & co that make us fat and reduce our lives, but being fat that leaves us insulin resistant, inflammed & co and thusly reduces our life-expectancy? The answer, according to Barziilai and Gaurav, is simple (Barzilai. 1999):In fact, all of the benefits of CR on