Study: Lean diet may mean long life

WASHINGTON -- It's never too late to cut back on the calories to prolong life, even in your later years, a study involving mice and low-calorie diets indicates.

In a study published Monday, researchers from the University of California, Riverside, said mice they put on a low-calorie regimen -- even creatures put on the diet for a short period -- exhibited characteristics of slowed aging.

Results from the study, published in the Proceedings of the National Academy of Sciences, suggest older humans could reap the benefits of such dietary changes as quickly as the mice, researchers said.

Research indicates that the sooner you cut back, the longer you may live, said Stephen Spindler of the university's biochemistry department. The widely held belief that restricting caloric intake extends life and health is backed up by research, he said.

"The bad news is, the longer you wait, the less time there is for the positive benefits to influence your aging," said Spindler.

VIDEO CNN's Rea Blakey has more on the findings of the study (September 4) Play video (QuickTime, Real or Windows Media)   RESOURCES Read more about the diet research in Proceedings of the National Academy of Sciences

Researchers put young and old mice on short- and long-term low-calorie diets, then observed changes in the genes of their liver cells, the study reported.

Restricting calories reversed the changes in several genes that were altered in aging animals, researchers noted. They also determined that older mice put on short-term, low-calorie diets demonstrated 70 percent of the anti-aging effects of the test animals that had been on a long-term reduced-calorie diet.

In other words, an old mouse on a low-calorie diet lived longer but not as long as one that started on the diet early in its life, researchers said.

The study is just the latest establishing a link between cutting back on calories and extending life.

Roy Walford, professor emeritus of pathology at the University of California, Los Angeles, has made headlines with a plan he calls CRON -- Calorie Restriction with Optimal Nutrition. Walford, who's been using animals to research weight loss and health since the 1960s, has suggested that people could live 120 years or longer if they maintain a weight that varies from 10 percent to 25 percent below their "set points," or the weight to which the body naturally gravitates.

The latest findings in Monday's study should not be construed as an invitation for people to eat as much or as often as they please, then cut back late in life, said Springer. Study findings indicate that cutting back sooner, rather than later, is the best way to extend longevity, he said.

Reuters contributed to this report.