Done right, aging needn't feel like a punishment. Studies show that people who live to age 100, as a rule, feel fine into their 90s. But commit crimes against your body — the body you're stuck with for as long as you survive — and the passing years can wreak havoc on your health before you're 50.

Some survival strategies require little elaboration:

• Maintain a healthy weight. Avoid coronary heart disease and other killer conditions associated with being overweight by keeping your weight in check: Eat fruits and vegetables and limit your intake of fat and calories. And work out regularly, being sure to combine stretching for flexibility, aerobics for endurance and weight training for strength.
• Don't smoke. Quitting reduces your risk of heart disease almost immediately, and over the years also reduces your chance of getting lung diseases, including cancer.
• Protect yourself from the sun's deadly rays. Age is a risk factor for skin cancer, a sometimes deadly condition that is diagnosed in more than a million Americans each year. To lower your risk, try to avoid unnecessary sun exposure, especially between 10 a.m. and 2 p.m. And when you are outdoors, wear a sunscreen with an SPF of at least 15.
• Don't drink to excess. While studies have shown that a single drink each day might not harm health — and might even have some beneficial effects — too much alcohol can damage almost every organ in the body and weaken the immune system.

Other strategies in the quest to stay forever young are not so simple, but are also within your power to affect.

"Until recently, we thought the best recipe for a long life was to have long-lived parents," says Daniel Perry, founder and executive director of the Alliance for Aging Research. "Now we know that a vast amount is up to us, by our choices, our behaviors and the environment we live in."

To help you age with ease, Discovery Health Online has uncovered the most up-to-date answers to these critical questions:

• What kinds of food and dietary supplements can help you live longer and stronger? End the confusion about which kinds of food can add years to your life, and which can actually harm health. Plus, which dietary supplements might help stave off illness, and which entail more risk than reward?
• Can extreme dieting and other new-fashioned habits lengthen your life span? Get the last word on a calorie-restriction diet that some people swear by and whole-body scans that promise to catch cancer while it's curable.
• When does forgetfulness become a cause for concern? Sometimes forgetting is normal and sometimes it's not. From expected memory lapses to those that might signal Alzheimer's, what steps can improve brain health?
• Staying happy, staying young. What has new research revealed about religion's effect on health and longevity? And how do marriage status, stress levels and other matters of spirit influence how long you'll live?