Bob Green's book 20 Years Younger
The longer I live, the more beautiful life becomes.

—Frank Lloyd Wright

Everyone has a notion of what it means to age. Whether it's a snapshot in your head of how your parents have slowed down or lines you see on your own face, for many people it has something to do with decline. Things not being the way they used to be. Everything less than before. A lot of people feel that aging is about loss. And in some ways it is. "Aging is a wide range of physiological changes that make us more susceptible to death, limit our normal functions and render us more susceptible to disease," says João Pedro de Magalhães, PhD, a researcher on the biology and genetics of aging and a lecturer at the University of Liverpool in England. I would add that the physiological changes that take place as we age can also render us more susceptible to psychological downturns. It's not uncommon for people to lose enthusiasm as they get older, disheartened by their physical deterioration and inability to live the way they used to.

Do we have to age? It's the $6 million—or maybe I should say $6 billion—question and it's one that researchers the world over are donating a lot of time and money to answering. Some scientists are even hoping to answer the inevitable next question: Do we have to die? I don't think we're all that much closer to immortality than Ponce de León was when he went searching for the fountain of youth in 1513. However, we do have a much greater understanding of the aging process. And we are living longer: Over the last 150 years, the average life span has climbed from about age 45 to closer to age 80.

Living longer is important, but the ultimate goal is to live longer and live well into your later years. And through the science of aging we now know that it's very possible. In fact, it's become clearer that not all the effects of aging we've come to expect are inevitable, and that by making certain lifestyle choices you can dramatically slow those effects down—and maybe, in some cases, even eradicate them. We all age—that is undeniable—but your likelihood of aging poorly increases if you decide to sit back and leave well enough alone. To the contrary, take action and you'll retain your vitality, age gracefully and, yes, have a longer, better life.

Each of the subsequent chapters in this book asks you to make certain lifestyle changes toward that goal. The reasons behind those changes will be clearer if you know a little bit about the theories of why we age and the physiological consequences of growing older.

Theories on Why We Age
Scientists have long debated a central question about aging: Why? Why do we age? Many of them, both past and present, fall into the evolutionary camp. In the late 1800s, a German by the name of August Weismann was one of the first to promote an evolutionary theory. He believed that we're programmed to age and die in order to make room for the younger generation, continuing the evolution and betterment of the species. You might call it planned obsolescence.

Over time, the evolutionary theory of aging has, well, evolved and other theories have risen to the fore. One, called the mutation accumulation theory, is based on the idea that undesirable genes that cause the death of children get weeded out; they're not passed on to the next generation. But undesirable genes that don't cause death until late in life get passed on from generation to generation because the people who have those genes have children before their death. Over successive generations, those genes have accumulated, predisposing people to contract diseases as they grow old, then die.

Another well-known evolutionary theory is called the antagonistic pleiotropy theory. Its central idea is that some genes may be beneficial to us in our early lives but detrimental to us as we grow older. For instance, genes that increase a woman's ability to reproduce may also ultimately lead to menopause and all the health hazards (among them, bone loss and an increased risk of heart disease) that go with it. According to the antagonistic pleiotropy theory, evolution may select for genes that favor youth because the chances that humans and other organisms will survive accidents, predators and disease to live long lives are slim (or at least they were before modern medicine).

The other major theories on why we age have less to do with evolution and more to do with the cumulative effects of damage to the body. Over the years, injury from simple wear and tear, sun damage, a poor diet, smoking, pollution, even the body's own metabolic processes, add up to promote aging and eventual death. One of the most prominent of these theories focuses on oxidative stress. Oxidative stress refers to the injury done to DNA, cells and tissues in the body by free radicals, molecules with unpaired electrons that are produced when the body metabolizes oxygen. Free radicals also become present in the body through all the injurious means I just mentioned (poor diet, etc.). In their incomplete state, free radicals become thieves, stealing electrons from other molecules and wreaking havoc along the way. The damage they leave in their wake is often compared to the rusting of metal. The body has the ability to absorb free radicals and repair the damage they do, but its defense system tends to weaken over time, leaving it vulnerable to disease.

Like all theories about the cause of aging, the oxidative stress theory is just that, theory. We don't know for sure if unbound free radicals are the main cause of aging; however, we do know that free radicals cause harm and that oxidative damage can certainly age your body, decrease your quality of life and even shorten your life span. More specifically, by damaging a cell's DNA, oxidative stress can be the first step to transforming a healthy cell into a cancer cell (cancer also has other causes, such as inherited genetic mutations).

Free radicals influence LDL (bad) cholesterol as well, making it even more prone to sticking to the walls of arteries and increasing the risk of heart disease, stroke, erectile dysfunction and other conditions. Many of the strategies you'll read about in this book are aimed at preventing and repairing free radical damage. I'll be recommending many foods that contain antioxidants such as vitamin E, vitamin C and certain phytonutrients that disarm and disable free radicals. These dietary watchdogs also boost the body's own free radical defense system.

Likewise, the exercise program will help turn up your body's own free radical-fighting capabilities. A lot of Dr. Lancer's skincare recommendations also focus on quenching free radicals that degrade collagen and elastin, the proteins that give skin its structure and bounce. In addition to free radicals, inflammation has been implicated in aging because of the role it plays in so many age-related diseases. (They're actually related—free radicals can cause inflammation.) Short-lived inflammation is a good thing; it's the body's defense against a flu virus, bacteria, a wound, a chemical irritant and other kinds of trauma. Inflammation occurs when, triggered by damage, immune cells rush into the injured area, releasing compounds that destroy bacteria or promote wound healing. When the condition resolves, the immune response goes away. At least, most of the time. Sometimes, for a number of reasons, inflammation persists. That's called chronic inflammation, and it's been linked to everything from cancer and heart disease to diabetes, dementia and even wrinkles. While it's far from certain that inflammation is the major culprit in aging, anything you can do to reduce inflammation—such as exercise regularly—will reduce the cumulative effects of aging.

In the evolutionary theory of aging, genes determine aging and, ultimately, death. In the damage theory of aging, factors such as unhealthy food, stress and even the body's own metabolic processes are the primary agents. However, many people, including me, believe that aging is a combination of both. All the recommendations in this book, in fact, are predicated on the idea that you are working both with your own genetic predispositions and with the things in life that you can control, such as what you eat and how much you exercise.