Why stop at 100?

Old is definitely the new young. A report on increased life expectancy published in the peer-reviewed British medical journal the Lancet earlier this month predicts that more than half of all babies born today will reach their 100th birthdays.

For the layman, this prediction may conjure a brave new world of hitherto unimaginable human longevity. For those more at home modeling the world of the future, though, it’s actually seen as a rather modest expectation.

“We have seen a linear increase in life expectancy for more than 150 years. And there’s no sign we’re close to a looming age ceiling,” says Dr. Kaare Christensen, the director of the Danish Aging Research Center and lead author of the report, on the phone from Odense, Denmark.

Dr. Terry Grossman and Ray Kurzweil, authors of “Transcend: Nine Steps to Living Well Forever,” go much further. “The estimate of 100 is absurd,” Mr. Kurzweil says, explaining that it is based on the present state of medical knowledge, which is bound to advance “exponentially” in the century ahead.

Mr. Kurzweil and others are working on medical technology that aims to change health outcomes on a cellular level. “Health and medicine is now an information technology,” Mr. Kurzweil, an inventor and futurist, says. “And information that fits in my cell phone today will fit in a blood cell in few years.”

In other words, the goal is no longer to treat diabetes, for example, with insulin, but to block the expression of diabetes by manipulating the body on a molecular and genetic level.

This, in turn, might just mean that you can “have your cake and eat it, too.” Obesity — no matter how much you eat — will not exist because we have reprogrammed our genes not to express it.

“There will be a quantum leap in evolution, and the world as we know it won’t be here in 40 years,” declares Dr. Grossman.

He predicts that by 2050, the only deaths we’ll see are accidental.

Wow. That’s a lot to take in.

Meanwhile, back in 2009, the increase in longevity forecasts can seem contradictory with rates of chronic disease and obesity increasing dramatically.

As it turns out, though, the advances in living standards, work environments, earlier and better medical interventions, overall education and decreased smoking rates among adults are trumping the troubling trends, Dr. Christensen says.

As for our latest chronic epidemic, there’s conflicting evidence on what exactly the health and morbidity outcomes are for obese people, says Richard Suzman, director of the Division of Behavior and Social Research at the National Institute on Aging.

“Some studies indicate that obesity leads to higher rates of disability, but not much higher levels of mortality,” Mr. Suzman says.

But even if we have become much more adept at treating chronic diseases with medication and other interventions, the one thing that tends to suffer when people are afflicted with chronic disease is quality of life.

And here’s where the familiar, common-sense preventive medicine tips come in: Eat right, exercise, get annual checkups.

Dr. Grossman and Mr. Kurzweil, while presenting what seem like sci-fi ideas on the future of medicine, dispense deceptively low-tech, almost homespun advice to citizens of 2009 in their book, including everything from supplements (which, they stress, should be tailored to individual needs as opposed to packaged in a multivitamin) to the need for strength, flexibility and cardio training.

“We have to take advantage of what’s available today and stay in good shape so we can take advantage of what’s available in 2040,” Dr. Grossman says. “Basically, the goal is to live long enough to live forever.”

Mr. Suzman says brain exercises and overall cognitive abilities are also important. Not only do they make for a more fulfilling old age, but they are also associated with cardiovascular health.

So, what do mainstream doctors and medical researchers such as Mr. Suzman and Dr. Christensen think about the prospects of future molecular and other high-tech interventions? While not denying their promise, they caution that they are one among many factors that afford hope for increased longevity.

“I hope it happens,” Dr. Christensen says. “But rather than believing in one magic bullet, I think we’re taking a lot of steps in the right direction. The molecular one, which is costly, is one of those steps.”

Increased longevity may come with a big price tag, but, says Mr. Suzman, “It’s a price everyone wants to pay,” so we’ll find a way, probably by upping the retirement age.