DOES DIETARY CALORIC RESTRICTION POSITIVELY IMPACT RISK OF DISEASE AND LONGEVITY?: A REVIEW OF THE LITERATURE.

Obesity has been linked to increased risk of disease and a lower life expectancy. Emerging research has shown that dietary caloric restriction (CR) may increase both life expectancy and reduce the onset of several chronic diseases such as diabetes, cardiovascular disease and cancer. The objective of this systematic review was to examine recent studies conducted using both animal and human models that explored the relationship between dietary caloric reduction and its impact on health. Science Direct, PubMed and EBSCO databases were searched for original research studies published within the last five years using the terms CR, CR and longevity, CR and disease and CALERIE. Six studies that were reviewed showed that a CR diet reduced metabolic aging and/or delayed onset of disease in rodent or non-human primates, compared to animal subjects that did not follow a CR diet. All studies maintained subjects on a 20% to 30% caloric restricted diet while maintaining adequate nourishment. The death rate was three times higher in non-human primates following a non-caloric restricted diet compared to a 30% CR diet. Study limitations include limited human research and challenges inherent to studying free-living human subjects. Most studies concluded that although there is a link between longevity and CR, future research is needed to examine why and how a CR diet works and to bridge the gap between studies conducted with animal models and human subjects.