Diminishment of colonic health is associated with various age-related pathologies. Calorie restriction (CR) is an efficient strategy to increase healthy lifespan, although underlying mechanisms are not fully elucidated. Here we report the effects of lifelong CR on markers of colonic health in aging mice. We show that 30% energy reduction, as compared to a control (C) and moderate-fat (MF) diet, is associated with attenuated immune-related gene expression and lower levels of bile acids in the colon. Pronounced shifts in microbiota composition, together with lowered plasma levels of interleukin 6, in mice exposed to CR are in line with these findings. Furthermore, expression of genes involved in lipid metabolism was higher upon CR as compared to C and MF, pointing towards efficient regulation of energy metabolism. Switching from CR to an ad libitum MF diet at old age revealed remarkable phenotypic plasticity, although expression of a small subset of genes remained CR-associated. This research demonstrates that CR beneficially affects markers of colonic health in aging mice and as such may attenuate the progressive age-related decline in health.