Sunday Nov 1, 2013 (foodconsumer.org) -- Both intermittent fasting and chronic calorie restriction may extend a person's life span.  A study published in the Journal of Nutrition in 1946 already found that intermittent fasting at the frequency of one in every three days increased the lifespan of male rats by 20% and female rats by 15%.

For the study, a group of 33 rats as controls were allowed to eat the same food ad libitum, that is, eat as much as they wanted to, and other three groups of 37, 37 and 30 rats were subject to intermittent fasting at different frequencies, one day in 4, 3 and 2 days, respectively.  The dietary intervention started at the age of 45 days, which is similar to 2 to 3 years for humans.

The best intermittent fasting frequency is one in every three days.  Male rats subject to intermittent fasting increased their life span by 20%, compared with 15% for their littermate females.   Anton J. Carlson and Frederick Hoelzel, authors of the study, noted that the pre-experimental condition of rats was also another important factor for determining their life spans.

No apparent growth retardation was observed in the groups who practiced intermittent fasting.  One more benefit from the intermittent fasting is that this restricted calorie intake retarded the development of mammary tumors.  A higher frequency of intermittent fasting resulted in more severe retardation of the mammary tumors, which is another benefit.

Recent studies have found more health benefits associated with intermittent fasting. They include normalization of insulin and leptin sensitivity, improvement of disease conditions, normalization of ghrelin - the hunger hormone, reduction in inflammation and damage induced by oxidative stress and blood fat or triglyceride and preservation of memory functioning and learning or cognition among other things.  Most notably, the risk of coronary heart disease and type 2 diabetes mellitus can be drastically reduced by following intermittent fasting or routine periodic fasting.

In the U.S., men and women on average are expected to live 78.6 years, two years shorter than their counterparts in Canada and United Kingdom although the U.S. spends much more money on healthcare.  According to a report by Reuters, the amount of money an average American spends on health care has reached more than $9,400 each year, almost one in 5 dollars on healthcare.  If the intermittent fasting benefits found in the study apply to humans, Americans may opt to live 94 years while reducing their food intake by 30%.  Also the healthcare expenditure for many chronic diseases can be reduced drastically. (David Liu, PHD)

Reference

Anton J. Carlson, Frederick Hoelzel, Apparent Prolongation of the Life Span of Rats by Intermittent Fasting: One Figure, J. Nutr., Vol. 31, No. 3. (1 March 1946), pp. 363-375 

http://www.eurekalert.org/pub_releases/2011-04/imc-sfr033111.php