FRIDAY, Nov. 2, 2007 (HealthDay News) -- Cutting back drastically on daily calorie intake can lead to longer life, at least in rats, say University at Buffalo researchers.
They speculate that this kind of diet can help maintain physical fitness into old age, slowing the progression to disability.
A lifelong 40 percent calorie-restricted diet reduced the rats' amount of visceral fat, which expresses inflammatory factors -- proteins that, in humans, cause chronic disease and an age-related decline in physical performance and vitality, the research team reported.
"This is the first study to report that caloric restriction reduced production in visceral fat of the inflammatory cytokine IL-6 and enhanced performance on overall physical function assessments," principal investigator Tongjian You, assistant professor of exercise and nutrition sciences in the UB School of Public Health and Health Professions, said in a prepared statement.
"In additions, rats that ate a normal diet lost a significant amount of lean muscle mass and acquired more fat, while calorie-restricted rats maintained lean muscle mass as they aged," You said.
The study was published in the October issue of Journals of Gerontology Series A: Biological Sciences and Medical Sciences.
While this severely-restricted diet proved beneficial in rats, You noted that people could not adhere to such a strict diet.
"Based on an average of 2,000 calories per day for adult women and 2,500 for men, cutting by 40 percent would mean surviving on 1,200 and 1,500 calories per day, respectively," You said. "It's very difficult for people to maintain that type of diet for short periods of time, and it would be nearly impossible over a lifetime, while staying healthy. Starting on a diet like that in the senior years would be harmful.
However, a more moderate 8 percent caloric restriction is achievable in people and may have a positive effect, recent research suggests.
The MedlinePlus Medical Encyclopedia has more about calories.