The #1 Secret To A Long, Happy Life + 3 Other Habits That Matter

By Josh Mitteldorf 

We’re at an exciting juncture for medical science. Life spans have been expanding for 150 years. We’re living seven years longer than our parents’ generation, and they lived seven years longer than their parents. We’re grateful for this—but we also want more.

In labs, scientists are significantly expanding animals’ natural life spans with cutting-edge genetics. We know how to modify the fertilized egg, snipping out genes that cause aging, providing extra copies of other genes. These tricks are routinely played with mouse embryos but have not yet been applied to humans.

There are technologies just over the horizon that may offer comparable benefits to adults. I’ve told my daughters to plan their lives with the expectation that they might live 200 years.

In the meantime—especially for those of us of a certain age—it’s crucially important to maintain tip-top health as long as we can. It’s not just the extra year or two of life that we might squeeze out in this way. It’s also the hope that we can be healthy and eligible for that next breakthrough when it arrives and enjoy lives that are not only longer but better.

So what is the single most important lifestyle factor that determines your prospect for a long, healthy life?


The joke says it’s “choosing the right parents.” But studies with twins suggest that the genetic component of life expectancy makes up only 25 percent. That leaves three-quarters of the range of possibilities under your control.

The longevity factors you can control

Of course, not smoking (or driving a motorcycle or taking up rock climbing) can play a major role in living longer. But they aren’t the biggest factors.


Keeping weight down can add several years to your life. But that’s relative to your body type. People who are overweight experience a social stigma in our culture. Sometimes they are overeaters, but it may be that they just have genes that make them stout. Mother Nature doesn’t have the same prejudices that people do. If you are overweight because you overeat, it will cut years off your life. But if you are dieting and exercising and doing your best with the genes you have, you may look like you’re overweight, but you probably don’t have the extra risks for heart attack and cancer.

Intermittent fasting also seems to be beneficial, even if you don’t lose weight. Avoid sugar. Vegetarians tend to live longer than meat eaters, and a high-fiber diet nurtures the right kind of bacteria in our guts for optimal health and longevity.


Yoga and meditation can help you become more intimate with your body. In fact, all kinds of exercise are helpful, and the more the better.

The most effective exercise of all is the most intense: interval training that leaves you panting after just one minute of all-out exertion, and strength training with the biggest weights your muscles can handle. Together, diet and exercise account for about a seven-year range of life expectancy.

Supplements and herbs:

Supplements are much less important than diet and exercise, but they could help. Vitamin D protects against colds and flu in the present and could guard against cancer and heart disease in the future. The amount of vitamin D you need may be way more than the 400 to 600 IU recommended by the FDA. Get a blood test, and monitor your levels with your doctor.

Optimal magnesium is elusive in the Western diet. Many biomolecules depend on magnesium, and our nervous systems depend on magnesium. Just 1 mg of magnesium each night could make a difference. You can get magnesium in pill form, or you can eat more leafy greens.

The jury is still out on nicotinamide riboside (NR) and n-acetyl cysteine (NAC). There are some herbs that might offer an edge, including curcumin, a powerful anti-inflammatory agent, and the active ingredient in the Indian root spice called turmeric; ashwagandha, an ancient Indian herb that is associated with brain health and longevity; rhodiola, a Chinese herb, an adaptogen that helps the body to respond more flexibly to the challenge of radiation or toxins; and bacopa, another Indian herb that may stimulate nerve growth and improve memory and brain function.

But the elephant in the room is a factor we seldom think about—because it’s not something you can buy, and it’s not something you can pursue with planning and willpower. It’s something our terribly individualistic American culture sweeps aside.

The single biggest factor that determines longevity in humans is social connection.

The biggest factor: social connection

People who are engaged in helping others have an enormous advantage in life expectancy. If you are in a loving marriage or embedded in a supportive community, this alone is worth almost a decade.

Caring for others is the reason we’re alive. Living a passionate, engaged life is a choice you must make from day to day, from hour to hour. This is an attitude not exactly encouraged in our culture—in fact, most of us were raised to do what’s expected of us, to be polite and conventional, to keep our feelings to ourselves and not make waves.

The economics of modern life make social fulfillment elusive. Choosing a different culture, a more empowering brand of politics—these are not individual but collective choices. We have to be willing to organize, and we have to work with others.

But social connections are what make us feel alive, and maybe we shouldn’t be surprised that they are also what can keep us alive.

If you’d like to learn more, check out my new book, Cracking the Aging Code, co-authored by Dorion Sagan.