These days, the average American man can expect to live for up to 74 years, while the average U.S. woman will see her 79th birthday, according to the Centers for Disease Control and Prevention (CDC). Although genetics and sheer luck play some part in life expectancy, our longevity also depends largely on the habits we incorporate into our daily lives.

Living to 100

Not everyone will become a centenarian, but those who live to be 100 years or older often say they have relied on the following habits to live full, healthy lives. Whether you're in your twenties or already a senior citizen, adopting these into your daily routine can add years.

Be a Healthy Eater. Consume a well-balanced diet with ample portions of fruit, vegetables, and whole grains; fat-free and low-fat dairy products; legumes; and lean meats such as fish and poultry. Try to get at least two servings of fish a week, preferably fatty fish that's rich in omega-3's, such as salmon. And avoid sugary beverages, which can spike blood sugar and calorie absorption. Research shows that a glass of red wine each day can increase your lifespan by up to four years.
Remain Active. At least 30 minutes of moderate exercise five days a week will help you stay physically fit. Overweight but fit people outlive those who are overweight but out of shape, but when it comes to increasing your lifespan, it's best to be slim and fit. Moderate exercise can include brisk walking, swimming, cycling, and gardening.
Be Lean. Pay attention to your caloric intake and energy expenditure, and resist the urge to overeat—even if you're working out every day. Focus on foods that provide a variety of nutrients, healthy unsaturated fats, and limited added sugar. Although calorie-restriction diets remain controversial, several studies suggest that limiting your caloric intake may add years.
Test Yourself. It's important to get regular checkups, as well as key exams such as cholesterol and blood-pressure tests. To lower your cholesterol levels, limit unsaturated fat, cholesterol, and trans fatty acids found in processed and packaged foods. To keep your blood pressure in check, reduce your sodium intake to no more than one teaspoon of salt per day.
Get Your Z's. A study conducted at the University of Chicago found that individuals who get six to seven hours of sleep a night live longer than those who sleep only four to five hours. So, it's important to make sleep a priority.
Quit Smoking. According to the Surgeon General, kicking the habit, even after decades, can reduce your cancer and heart-disease risk and increase your life expectancy. For best results, talk with your doctor about smoking-cessation options.