Could caloric restriction be the most reliable health and longevity approach that we have available right now while we wait for medical technology to progress? A new review suggests that “calorie restriction is the most reasonable anti-ageing intervention”.
Is this the best we can do for now?
A new meta-analysis of caloric restriction studies has been published, and it reviews a number of caloric restriction studies in fruit flies and flatworms. While the researchers indicate that they would like to expand the analysis to include rodents and other species, this initial data is useful nonetheless.
While this review is focused on other species, the practice of caloric restriction is known to convey significant health benefits in humans . The effects of caloric restriction on lifespan, unfortunately, do not scale so well; we see significant increases of lifespan in animals like worms, flies, mice, and short-lived primates , but longer-lived species have less impressive increases; in humans, this may translate to perhaps a few years.
That said, while it is unlikely that caloric restriction or similar dietary approaches will bring decades of life, as we would have noticed this already in societies with less access to food than typical Western nations have, it may add more healthy years and possibly even a modest increase in lifespan.
Despite technological advances, the survival records from longevity experiments remain the most indispensable tool in ageing-related research. A variety of interventions, including medications, genetic manipulations and calorie restriction (CR), have been demonstrated to extend the lifespan of several species. Surprisingly, few systematic studies have investigated the differences among these anti-ageing strategies using survival data. Here, we conduct a comprehensive and comparative meta-analysis of numerous published studies on Caenorhabditis elegans and Drosophila. We found that CR and genetic manipulations are generally more effective than medications at extending the total lifespan in both models, and CR can improve the ageing pattern of C. elegans. We further analysed the survival variation for different anti-ageing medications and determined that hypoglycemic agents and antioxidants are advantageous despite only moderately increasing the overall lifespan; therefore, these two types of medications are promising CR mimetics. Analysis of genetic manipulations also indicated that the genes or pathways that extend lifespan in a healthier pattern are associated with CR. These results suggest that CR or CR mimetics may be the most reasonable and potentially beneficial anti-ageing strategy.
Given that more robust therapies based on the repair of age-related damage are in development, it seems sensible to do whatever we can now to buy us time so that we are alive to benefit from the arrival of these advanced technologies.
Just like exercise, caloric restriction is a low-cost health and longevity strategy and provided that it is done properly with careful monitoring of nutrition to avoid malnourishment, it has many potential health benefits.
 Liang, Y., Liu, C., Lu, M., Dong, Q., Wang, Z., Wang, Z., … & Wang, X. (2018). Calorie restriction is the most reasonable anti-ageing intervention: a meta-analysis of survival curves. Scientific Reports, 8(1), 5779.
 Ravussin, E., Redman, L. M., Rochon, J., Das, S. K., Fontana, L., Kraus, W. E., … & Smith, S. R. (2015). A 2-year randomized controlled trial of human caloric restriction: feasibility and effects on predictors of health span and longevity. The Journals of Gerontology: Series A, 70(9), 1097-1104.
 Pifferi, F., Terrien, J., Marchal, J., Dal-Pan, A., Djelti, F., Hardy, I., … & Zahariev, A. (2018). Caloric restriction increases lifespan but affects brain integrity in grey mouse lemur primates. Communications Biology, 1(1), 30.