Obesity as an Aging Accelerator

Obesity is a health condition caused by a combination of intrinsic and extrinsic factors, and in turn involved in the onset of a number of other diseases, especially cardiometabolic ones and cancer, and in the increase of mortality. For this reason, it can be considered as a factor speeding up the aging process in humans and in animal. This chapter explores the biological ways through which this process takes place, with a particular focus on the relation of obesity with markers of biological age and with the studies that related the caloric restriction in the diet with longevity. About the markers of biological aging, we focus on telomeres length and on epigenetic clocks, discussing their reliability as indicators of biological age, and reporting some evidence of their relationship with obesity onset and prevalence. For what concerns caloric restriction, we review the biochemical mechanisms that can play a role in how a modification in the diet is able to affect longevity. We focus on one aspect of the experimental studies on caloric restriction: usually the restricted animals are compared with animals with free access to food (ad libitum condition), these last ones are on average way heavier than their counterpart found in nature. Therefore, we propose to “flip the paradigm”, considering that an exaggerated caloric intake unleashes a set of biochemical mechanisms causing both obesity and an acceleration of the aging process, ultimately shortening lifespan.