old age, longevity, living longer

Eat Less to Live Longer

July 10, 2009 07:30 AM
by Shannon Firth
Studies show that calorie restriction may help delay the aging process. Instead of trying to delay the inevitable, shouldn’t we try to enhance the quality of our waning years?

What Animals Can Teach Us About Longevity

According to Science News, two decades of research by scientists at the University of Wisconsin-Madison demonstrated that monkeys given a regular diet had three times the risk of death from age-related diseases than monkeys fed a calorie-restricted diet.

“I’m confident that everything that happens in [non-human] primates will happen in humans,” Luigi Fontana of Washington University in St. Louis told Science News. Furthermore, people who shift from the typical high-fat Western diet to a nutritious restricted diet “may experience even greater health benefits than seen in this study,” according to Science News.

The study, slated for release July 10 in Science magazine, may bolster a recognized theory that reducing calories—naturally or chemically—curbs metabolic activity, which in turn prolongs life.

Brian Delaney, president of the North Carolina-based Calorie Restriction Society, told The Wall Street Journal, “It's all consistent with what human practitioners of calorie restriction have always believed."

In a second study by researchers at universities in Maine, Michigan and Texas, rapamycin, a drug used to help prevent rejection by the immune system in organ transplant patients, has prolonged life in mice by 9 percent for males and 14 percent for females, The Wall Street Journal reported. 

According to Science News, this is the first time that a drug with the ability to replicate the effects of a reduced calorie diet has been found to prolong life in mammals.

Tina Hesman Saey, writing for Science News, explained, “Rapamycin targets an energy-sensing protein called TOR, perhaps tricking cells into thinking their calorie intake has been cut.”

There are some drawbacks to the discovery. Matt Kaeberlein, a molecular biologist at the University of Washington in Seattle, told Science News, “Most people don’t want to live an extra 10 years of frailty in old age, what we want is another 10 years of youth and vitality.”

In a 2004 editorial for The Guardian, writer Guy Brown noted a study that showed the “additional years we gain are mostly spent with disability, disease and dementia.” According to the Office for National Statistics (ONS), between 1991 and 2001, the life span in Britain increased by 2.2. years, but the “healthy life expectancy increased by only 0.6 years, with the other 1.6 years being spent in ill-health.”

Brown argued, “If society really cared about the last 10 years of life… then we would have a real chance of preventing the end of life becoming a living death.”

Background: How does diet affect aging?

Writing for The Philippine Star, Dr. Tyrone M. Reyes explained that aging occurs when the body’s restorative mechanisms are unable to keep up with regular damage to our DNA and other essential “building blocks” such as proteins and lipids.

The process of making energy from caloric fuel, says Reyes, although necessary for life, also releases free radicals, which he described as “destructive, oxidizing molecules.” According to Reyes, “This gradually impairs the functioning of cells, tissues, and organ systems, thereby increasing vulnerability to disease and giving rise to the characteristic manifestations of aging,”

Opinion & Analysis: Weighing the pros and cons of calorie restriction

How is calorie restriction different from Anorexia Nervosa? According to Matthew Tiemeyer, an eating disorder specialist writing for, “The anorexic person will desire to lose weight at all costs, with no regard for health, safety, or any other concern.”

Still, the level of self-deprivation practiced by CR enthusiasts can be too extreme for some. Tiemeyer suggests an alternative to a CR diet such as following the practice of intuitive eating. He explains that those who follow intuitive eating often feel more in tune with their bodies. “The body knows what it needs, and the mind and body are much better at identifying needs together than a rigid meal plan.”

The Calorie Restriction Society advocates eating more nutrient-rich, lower calorie foods, such as vegetables and select proteins and fats to achieve a longer, healthier life. The Society’s Web site presents the risks of the lifestyle, which include possible reduced bone mass, sensitivity to cold, less “cushioning” when seated, possible infertility and decreased testosterone.

The site also warned of “anecdotal reports” of psychological problems associated with the diet, such a bingeing, anorexia and “excessive food thoughts and fantasies,” and does not recommend the lifestyle for people under 21 years of age.

Related Topics: SENS; Longer life for worms

Dr. Aubrey de Grey’s theory, known as Strategies for Engineered Negligible Senescence (SENS), believes humans could live to be a thousand years old. 

In a 2006 interview, Morley Safer of “60 Minutes” asked de Grey if we can expect to be as spry as we are at 25 at 500. “[T]hink about the situation with houses. With moderate maintenance they stay up, they stay intact, inhabitable more or less forever … And it's going to be the same with us.”

In 2008, scientists at Harvard Medical School’s Joslin Diabetes Center said that worms whose insulin levels were lowered increased their life span from two to three weeks. "It doesn't sound like much for a worm, but those percentages would be a lot for us," said study coauthor Dr. T. Keith Blackwell.

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