02/13/2011 10:26 am ET | Updated May 25, 2011

Restricting Calories to Live Longer: Does it Work?

With the demand for various anti-aging products and procedures at an all time high, our obsession with prolonging our lifespan and aging gracefully is greater than ever. But what if the ultimate answer to achieving the fountain of youth lies simply in the amount of food you consume?

Caloric restriction, not to be confused with starvation, has been a hot topic in anti-aging research for decades. Now, 70 years after its initial finding, caloric restriction remains the most effective natural intervention for increasing longevity. Numerous studies on a diverse range of species have proven that a calorie restricted diet (without malnutrition) delays the symptoms of aging and increases lifespan and decreases chances of metabolic diseases and cancers.

Recent developments include the observed increase in the lifespan of Rhesus Monkeys, along with delay in the onset of diabetes, cancer, cardiovascular diseases, and brain atrophy. Not only were these calorie-restricted primates healthier and surviving longer, they also looked much younger than their freely-fed peers, and yes -- they had less wrinkles. Given the numerous similarities between humans and monkeys, this study provides useful insight into similar mechanisms in the human aging processes. Further, a 2007 study on human calorie restriction showed that reduced-calorie intake has a profound effect on secondary aging and the onset of atherosclerosis and diabetes.

So what is it about decreasing our caloric intake that has such drastic effects on our aging process? One mechanism related to caloric restriction is its impact on sirtuin levels. Sirtuins are proteins known to be associated with regulation of both metabolism and stress homeostasis, and have been linked to the observed increased life spans in a range of species from yeast to mice. Seven forms of sirtuins have been located in humans and have been identified in playing key roles in energy homeostasis in metabolic tissues. Work done by the McBurney Laboratory showed that mice lacking the sirtuin known as SIRT1 were metabolically inefficient in comparison to those expressing it that proved to be leaner and more metabolically active. Further, mice mildly overexpressing SIRT1 seemed to be protected from metabolic diseases at an older age, even when challenged with a high-fat diet. One way these anti-aging sirtuins are activated is through a mechanism triggered through caloric restriction.

What exactly does caloric restriction mean? Caloric restriction is defined as a moderate (20 percent-40 percent) reduction in caloric intake, without compromising the maintenance of any essential nutrients. Since everyone's caloric intake and nutrient requirements are different, there is no one generic formula. The most important aspect to incorporate into your daily eating habits is making sure you never eat to or past a point of fullness. Also, aim towards eating smaller meals with a lower caloric density and high nutrient density. This can be achieved on a more plant-based diet, rich in vegetables and whole grains. Also, avoid eating meals with too many unknown ingredients. Many times restaurants add excess oils and ingredients that make a seemingly healthy meal much higher in calories than you would expect.

Finally, it has also been proposed that aerobic exercise is an effective way to improve the production of certain sirtuins. A 2010 study on marathon runners displayed a significant increase in SIRT1 production post marathon.

Maintaining a healthy energy balance of calories in and out through conscious eating and exercise not only aid in sirtuin mechanisms and metabolism maintenance, but also prevent the deterioration of physiological fitness during the process of aging including oxidative damage, inflammation and lack of protein turnover. These factors are what contribute to our disease susceptibility and our overall aging as well.

So there you have it! More proof that what you eat, how much you eat, and physical activity are the most effective non-pharmaceutical way to age gracefully and live longer.

Find more information on natural ways to stay young looking and feeling at Jay Williams, Ph.D. The 24 Hour Turnaround.

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