A low-calorie diet has been shown to boost health, but it doesn’t appear to prolong life — at least not in rhesus monkeys — according to a new study into a possible link between food restriction and longevity.
The research spanned 23 years and found that monkeys who ate fewer calories than non-dieting counterparts were healthier but did not have a longer lifespan, reports Yahoo! News.
Rhesus monkeys are popular for lab studies because they are long-lived primates, much like humans. Their normal lifespan in captivity is 37 years with the maximum being 40 years.
The study was launched in 1987 by the National Institute on Aging (NIA) in Maryland and involved monkeys of different ages that were fed a diet 30 percent lower in calories than others, who followed a “normal” nutritious diet.
Animals in both groups lived longer lives on average than wild rhesus monkeys and were also heavier. No monkey was malnourished, and they were all given vitamin and mineral supplements, according to the researchers’ report in the journal Nature.
Monkeys on the low-calorie diet were healthier, showing a lower incidence of diabetes, cardiovascular disease, and cancer than those given a normal diet. Males also had lower cholesterol than normal diet monkeys.
Rafael de Cabo of the NIA’s Laboratory of Experimental Gerontology stated, “However, these effects did not translate directly to a beneficial effect in longevity when compared with the control monkeys.”
The New York Times notes that the study yielded different results than one published in 2009, which suggested a low-calorie diet lengthened the lives of monkeys. Steven Austad, interim director of the Barshop Institute for Longevity and Aging Studies at the University of Texas Health Science Center in San Antonio, stated: “This shows the importance of replication in science”
Dr. Austad was not involved in either study but said that the University of Wisconsin study in 2009 “was not nearly as conclusive as it was made out to be.” He also said that the results serve to question the idea that a low-calorie diet would lead to longevity.