Calorie Restriction as a Means to Longevity

Science Shows Weight Loss of 10% Below Setpoint Slows Aging

Nov 13, 2009

Calorie restriction research in adult mice shows that eating small amounts of nutrient-rich foods helps drop pounds below normal weight and can help humans live longer.

Famous for his participation in Biosphere 2, Dr. Roy Walford studied mice and found that a gradual calorie restriction begun in adulthood resulted in younger-acting animals who lived more than one third longer than mice eating a normal diet. Dr. Walford concluded that being lean, while adequately nourished, extended lifespan. Life-extension became a category of ideas aimed at living a long and healthy life. With his wife Lisa and philosopher Brian Delaney, Dr. Walford called his anti-aging nutritional program the CRON diet, which stands for Calorie Restriction with Optimal Nutrition. The CRON diet plan shows promise for lowering blood pressure, normalizing blood sugar and reducing serum cholesterol, reversing conditions associated with overweight and aging.

CRON is A Lifestyle, Not a Diet

Since calorie restriction should be done gradually, ideally over one to two years, this is not a short-term endeavor to lose weight. Benefits of longevity attributed to calorie restriction also are not promised to those who keep calorie intake the same while increasing exercise, despite the fact that such a strategy is a valid weight-loss plan. Starvation is also not in the CRON plan, although periodic fasting is considered an acceptable way to reduce overall calorie intake. Dr. Walford theorized that humans have a setpoint, or weight that remains relatively stable if they eat a normal diet. Longevity is achieved by dropping as little as 10% below the setpoint weight. As much as a 25% reduction is considered reasonable by CRON advocates. A 20% restriction of calories over time is the key to weight loss on the CRON diet plan. While calorie count is individualized, generally a daily intake in the 1500-1800 range is advised.

Nutrient-dense foods are at the heart of calorie restriction. Lean sources of protein, limited high-quality fats, and large helpings of high-fiber vegetables are the foundation of the CRON diet. Free software is offered by the Calorie Restriction Society to help calorie restrictions dieters track the nutritional content of the meals they consume.

Dr. Walford's Work is Controversial

Basing his studies on experiments done in the 1930s, which accidentally revealed that mice who ate less lived longer, Dr. Walford's early attempts with calorie restriction in mice did not show longer lifespans. This was believed to be because of too rapid weight loss, which is difficult for the body to adjust to, and which releases toxins from fat cells too quickly. Dr. Walford died in 2004 at the age of 79 from complications of Lou Gehrig's disease. Until recently, no human studies had validated theories inspired by his studies on more than 50 species of animals. Currently, research in humans and chimpanzees hopes to remedy this gap. Since they are monitoring lifespan, as well as youthful vitality and calorie restriction, the studies will take decades to complete.

Roy L. Walford, M.D., Beyond The120 Year Diet: How To Double Your Vital Years, Da Capo Press, 2000

The copyright of the article Calorie Restriction as a Means to Longevity in Diet Trends is owned by Mary Earhart. Permission to republish Calorie Restriction as a Means to Longevity in print or online must be granted by the author in writing.