by Robert Bazell, NBC News Chief Science Correspondent
Tonight, we report the latest in research into possibly prolonging life by drastically restricting caloric intake. For more than 70 years scientists have known that the one thing that makes lab animals --from worms and fruit flies to rats and mice -- live longer is to put them on a calorie-restricted diet.
Today we focus on the latest studies involving rhesus monkeys at the University of Wisconsin Regional Primate Center. It is important to note that this research does not involve the equivalent of a person going on a diet to lose weight. In the studies, animals get about three quarters of the amount of calories that would normally be necessary to maintain body weight but with nutritional supplements so they do not suffer from vitamin deficiencies or other problems that can come with an inadequate amount of food.
The monkeys on the calorie restricted diet so far have less diabetes, heart disease and other health problems. The experiment began in 1989 and so the monkeys are approaching the end of their normal lifespan and soon the longevity data will be in.
Already there is a small group of people who so believe in the calorie restricted diet they are trying it themselves. In our piece tonight we feature a couple Meredith Averil and Paul McGlothin who have been on the diet for 14 years. They have a book called "The CR Way" coming out in the spring and you can checkout their Website. We have far more video of our interview with the couple here.
Most Americans would find it difficult to eat so little for so long for an uncertain result.
Years ago I did a story about Dr. Roy Walford, a professor the University of Southern California and then UCLA, one of the earliest proponents of calorie restriction for humans. He told me by eating less, he planned to live to 150, but sadly he died at age 79 from complications of A.L.S.
Whether or not the restricted diet appeals to many people, the research in animals is yielding interesting results. Yesterday scientists from Harvard and Weill Cornell medical schools published the discovery of two genes that seem to be switched on by calorie restriction. This could lead to a better understanding of the process of aging.