With all of the media attention presently (and no doubt temporarily) given to the practice of calorie restriction, I thought I'd point out an interesting open access paper on this topic. Comparatively little of the literature on calorie restriction that passes through my neck of the woods is written from the perspective of the cancer research community, so you may find references to research results you weren't previously aware in this review.
Over the last several years, new evidence has kept pouring in about the remarkable effect of caloric restriction (CR) on the conspicuous bedfellows - aging and cancer. Through the use of various animal models, it is now well established that by reducing calorie intake one can not only increase life span but, also, lower the risk of various age related diseases such as cancer.
Cancer cells are believed to be more dependent on glycolysis for their energy requirements than normal cells and, therefore, can be easily targeted by alteration in the energy-metabolic pathways, a hallmark of CR. Apart from inhibiting the growth of transplantable tumors, CR has been also shown to inhibit the development of spontaneous, radiation, and chemically induced tumors.
The question regarding the potentiality of the anti-tumor effect of CR in humans has been in part answered by the resistance of a cohort of women, who had suffered from anorexia in their early life, to breast cancer. However, human research on the beneficial effect of CR is still at an early stage and needs further validation.
Though the complete mechanism of the anti-tumor effect of CR is far from clear, the plausible involvement of nutrient sensing pathways or IGF-1 pathways proposed for its anti-aging action cannot be overruled. In fact, cancer cell lines, mutant for proteins involved in IGF-1 pathways, failed to respond to CR. In addition, CR decreases the levels of many growth factors, anabolic hormones, inflammatory cytokines, and oxidative markers that are deregulated in several cancers.
The authors go on to discuss the means by which calorie restriction might beneficially impact the odds and progress of cancer. There is a great deal of data, but room enough in the remaining uncertainty to argue the case for calorie restriction's effects on cancer to be caused by either (a) the same mechanisms as extend longevity, or (b) some completely different set of mechanisms. There is plenty of room for writing grants here also, given the growing willingness of funding bodies to pay for research into the many and complex relationships that link metabolism with aging and longevity.
Now if the research community would only pay as much attention to plans for research that might actually extend life significantly, rather than just obtain more data on the operation of the human body...