In a land where food abounds, a small but growing group is taking a different approach to eating. Proponents of calorie restriction, or CR, seek longer lifespans through what some might describe as semi-starvation. Though the mechanisms behind CR remain unclear, proponents say it puts us one step closer to the illusive fountain of youth.
Calorie-Restricted Diets
A calorie-restricted anti-aging program entails eating a diet low in calories and high in vitamins and minerals. One hypothesis suggests that a decreased metabolic rate will reduce oxidative damage to DNA. According to a review published in the journal "Physiology and Behavior," prolonged CR has been shown to increase the lifespan of lower species such as worms, monkeys and mice. The CALERIE study, or "Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy," is underway as of 2010 to assess the application of CR in human subjects. Preliminary results indicate favorable changes in body composition, cognition, diabetes indices and risk of cardiovascular disease.
The Skinny On Calorie Restriction
In contrast to typical diet programs, the goal of CR is to slow the aging process. The Calorie Restriction Society argues that weight loss is merely a side effect. Practitioners typically restrict caloric intake by 20 to 30 percent only after improving dietary quality. Dr. Lisa Walford, board member of the CR Society, advises followers to aim for a body weight 10 to 25 percent below their current set point.
What's On The Menu?
The tenets of CR involve getting the most bang for the calorie buck. The CR Society recommends avoiding simple sugars and refined flour while eating a diet loaded with vegetables and small portions of quality protein. Limited doses of healthy fats from nuts, fish and olive oil are allowed. Subscribers use caution not to exceed their calorie goal, but choose nutritious foods to avoid vitamin and mineral deficiencies. Regular blood work is encouraged to chart progress.
Risks
A CR diet is not without risk. Despite its potential health benefits, MayoClinic.com warns of hormonal imbalances, bone and muscle loss, anemia and dizziness. Because eating is an integral part of Western culture, some have experienced a dampened mood and social isolation. Eating disorder symptoms may also emerge. While some have equated the lifestyle to anorexia nervosa, the CR Society claims the pursuit of health---not thinness---drives its mission.
Real-Life Relevance
Human evidence of CR's efficacy lies in the Japanese islands of Okinawa, sites Redman and colleagues. With a nutritious diet low in calories, the Okinawan's boast four to five times more centenarians than other industrialized nations. Despite the promising health potential of the CR diet, Redman questions its feasibility. With fast food chains at every corner and vending machines just steps away, some lack the discipline and persistence necessary to induce CR's postulated effects. Nevertheless, the health implications to humans continue to intrigue researchers.
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