Voluntary food restriction does not affect circulating corticosterone in obesity-prone or -resistant male and female rats.

Food restriction in rodents can increase circulating corticosterone, which reflects activation of physiological stress responses. These responses affect a myriad of behaviors and physiological processes and can increase the risk of obesity. Most of these studies have used experimenter-imposed restriction. However, rats will voluntarily restrict their food intake if they are returned to chow after a period of access to sugary, fatty "junk food" (JF) diet. Here we examine the effects of voluntary food restriction in obesity-prone and -resistant rats on circulating corticosterone concentrations and determine whether corticosterone release in response to acute stress differs in groups with a history of JF consumption.