With the growing interest in calorie restriction research and related biomedicine, more scientists are stepping up to theorize on the effects of CR on human life span. "The question has arisen in the literature as to whether dietary restriction (DR) will have a significant effect on human longevity. ... human reproductive costs are high enough to permit a DR response. I then review four different models relating diet and life span, three of which have been previously used to estimate the effects of DR on humans. A review of the pertinent literature suggests that these three models, while plausible, are not capable of making robust predictions that are consistent with human data not used in their development. ... The fourth, or biocultural model, examined combines biologic and cultural factors. Human longevity is more complex than our model systems have led us to believe, and thus any solution will require the development of a new quantitative model. ... If the human cultural pro-longevity practices can be quantified in terms of their effect on energy allocation, then this model may serve in future as a realistic quantitative model capable of identifying pertinent pathways and making robust predictions." I predict that by the time a robust prediction of the degree of extended human life span to be obtained through the practice of CR has arrived, it will be rendered irrelevant by advances in rejuvenation medicine.

Link: http://www.ncbi.nlm.nih.gov/pubmed/17665968