The quest for eternal life looms large in human imagination -- from Egyptian burial tombs and mummification to Ponce de Leon's search for the Fountain of Youth to today's breakthroughs in genetic engineering and medicine.
As technology and science advance, some believe we're getting closer to living significantly longer -- even eternally. But are we still tilting at windmills in trying to hold off the inevitable, with technology offering little more than new-fangled snake oil?
Here are some of the more recent, and unique, efforts to stop the aging clock.
Calorie-Restrictive Diets -- People who practice caloric restriction, or CR, believe they can slow down the aging process by significantly cutting calories from their diets.
CR is based on animal research that shows rodents and other animals on a low-calorie, high-nutrient diet live about 30 percent longer than regular rats.
The CR regime is comparable to not pushing your car too hard -- the less fuel you burn, the less wear and tear on your body. Many who practice CR say they feel better and more energetic on the diet.
"I have more energy than I ever dreamed would be possible to have at any time in my life," says Paul McGlothin, a 57-year-old who has been practicing CR since 1994.
Dr. Roy Walford, a scientist at the University of California, Los Angeles, pioneered the study of CR in the late 1980s. His daughter, who co-authored "The Longevity Diet," is 50 years old and has been on the diet for over 15 years.
Lisa Walford stands at just under 5 feet tall and weighs 80 pounds -- about 15 pounds less than an average woman her height. She stresses caloric restriction is not the same as anorexia -- she eats throughout the day, but consumes only about 1,300 calories in foods like nuts, fruits and vegetables, and she is an avid practitioner of yoga.
Dr. David Katz, a nutritionist from Yale University, says the jury is still out on how healthy caloric restriction is for humans.
"The verdict is not in in terms of longevity, and the reason for that is that it will take 120 years to see if people can live 120 years on this diet," Katz said. "Short term, it improves cardiac risk factors and it has the prospect of extending life."
The diet does have certain side effects for most people, including being cold from lack of body fat, a reduced sex drive and loss of bone mass, which can lead to osteoporosis and breakage.
Plus, there are not many of us who can maintain the rigors of eating far less food. "It's unrealistic for a public that we can't even talk into moderation, let alone severe calorie restriction," Katz said.
Cryonic Suspension -- Cryonic suspension puts your body on ice until medical science advances enough to cure the ailments of aging. In theory, you'll be frozen, stored, thawed, repaired and revived, ready to get back to the business of living.
Admittedly, cyronics is a "speculative life support technology," says the Alcor Life Extension Foundation, one of five companies in the country that offers the service.
In the cryonics process, a dead body is slowly cooled to a chilly -166°F using liquid nitrogen. Cryro-protectants are then pumped through the body, which is immersed head first in a stainless-steel vat of liquid nitrogen and stored at -320°F.