Low-calorie Diet For Longevity

Low-calorie diets have demonstrated the most consistent results in achieving increased life span and vitality, according to a June 2006 study by Byung Pal Yu published in the journal "Biogerontology." Since the 1930s, researchers have studied the idea that restricted-calorie diets increase an individual's lifespan by reducing inflammatory processes that typically lead to degenerative, chronic conditions associated with aging. The exact mechanism responsible for the positive outcomes has eluded scientists, however, and reproducing the effect in human studies has proven difficult.

History

Initial study of the positive effects of calorie restriction, or CR, began in 1935 at Cornell University when Clive McCay and Mary Crowell experimented with the diet on rats, according to the CR Society, a calorie restriction advocacy group. Rats that were fed a severely restricted diet supplemented with appropriate levels of micronutrients lived twice as long as the control group. They also maintained a youthful appearance and high energy levels far beyond their anticipated life span.

Development

Fifty years later, Dr. Roy Walford and his student Richard Weindruch conducted further studies, first on mice, then on additional mammalian groups. The pair confirmed the effect in their 1988 book, "The Retardation of Aging and Disease by Dietary Restriction."

Initially, Walford's research resulted in shortened life spans of adult mammals, which he determined was a failure of the animals to assimilate to the new program. Young mammals had no such difficulty, and when CR was introduced gradually in adults, Walford was able to replicate the results found in immature specimens.

Human Trials

As of 2010, results of CR in human trials haven't produced the homogeneity of those conducted on rodents and other mammals. Testing methods and the severity of the restriction may be to blame, according to Byung's research. However, studies have resulted in increased understanding of the aging process. The extensive research has helped identify biological markers that may influence age-related inflammatory responses, which are favorably influenced by CR.

Methods

You can practice calorie restriction by following a strict daily diet that reduces your caloric intake by 60 percent, or by fasting several days a week to lower your average caloric intake. The fasting method, when applied to rodents in lab studies, produced results similar to the fully restricted diet plans; however, test groups that were fed reduced calories each day logged better overall results in functional longevity. Consult your doctor before changing your diet.

Theories

A 2007 study conducted by Cornell Medical School and the National Institutes of Health reported the most concrete findings to date--as of 2010--on the causes of inflammatory response and its effect on aging in humans. The team isolated two genes--SIRT3 and SIRT4--present in mitochondria, or the cellular structure that drives cell activity. The genes produce enzymes that promote cellular health and stave off the natural rate of "cell suicide" that affects all living organisms. According to the study, which was published in the journal "Cell," researchers aren't sure why CR activates these two genes in particular, but the effect is similar to results observed in studies related to exercise and cellular health.