I will echo Ingram and Roth on this topic and use this post as a future reference. Both were involved (principal investigators, I believe) with the CR primate studies. (emphasis mine)
The long-term study of rhesus monkeys at the University of Wisconsin reported significantly reduced morbidity and mortality in those monkeys maintained on 30% CR from adult ages (7–14 years of age) compared to controls (Colman et al., 2009 and Colman et al., 2014). In contrast, a report from the long-term study of rhesus monkeys from the NIA that we initiated in 1987 found no evidence of improved survival in monkeys initiated on 30% CR from young ages (2–6 years) or older ages (14–21 years) (Mattison et al., 2012). Differences in the design of these studies, particularly the dietary composition, are now being investigated to uncover reasons for the different outcomes. Even if the conclusion is ultimately that CR does not significantly extend lifespan in rhesus monkeys, there is ample evidence from these studies to demonstrate improved health and function at older ages in monkeys on CR.
1. Ageing Res Rev. 2015 Mar;20C:46-62. doi: 10.1016/j.arr.2014.11.005. Epub 2014 Dec 19.
Calorie restriction mimetics: Can you have your cake and eat it, too?
Ingram DK, Roth GS.