Proper nutrition and regular exercise can have a powerful impact on our longevity, but there are other regular habits that can help to not only lengthen lifespan, but improve quality of life as well. Dr. David Agus, a physician and professor of medicine and engineering at the University of Southern California, believes there are "several such ways to delay and prevent disease," which he outlines in his books, The End of Illness and A Short Guide to a Long Life. Here is his prescription for a longer, healthier life.

1. Improve your posture
Turns out that mom was right: Sitting up straight really is important. Dr. Agus believes it's "one of the best-kept secrets for achieving a longer, healthier, and more enjoyable life." Bad posture can lead to back and neck issues, as well as headaches, indigestion, poor circulation—and even neurological problems. "Your body was designed so that when you sit up straight, the heart and lungs work better. When you lean over, your body doesn't work as well," explains Dr. Agus. "That simple act of maintaining posture over time actually improves and lowers your risk of disease."

2. Eat for your metabolism
Dr. Agus maintains that a crucial aspect of good health is eating at regular intervals. "The data are clear: If you had lunch at noon yesterday and you eat at three o'clock today, your body's stress hormones will go up, and they will stay that way for several days." This response can negatively impact cognition, reduce exercise performance and lower your metabolism, making it harder to lose or maintain an ideal weight. "It doesn't matter if you eat five meals a day or two meals a day, it's the regularity that's key," stresses Dr. Agus. And that regularity applies to your sleeping habits, too.

3. Have a drink—in moderation
There's conflicting evidence about the health benefits of alcohol. So is it a good idea to imbibe? "A small amount of alcohol consumption on a regular basis does have a benefit in terms of reducing one's risk for heart disease," confirms Dr. Agus. The key here is moderation. If you choose to drink, stick to Canada's low-risk alcohol drinking guidelines: Women should limit themselves to two or fewer drinks a day, up to a maximum of 10 per week. (Women who are pregnant or breastfeeding are advised not to consume alcohol.) Dr. Agus recommends no more than one drink a day for women, and two for men.

4. Avoid stilettos and other sneaky sources of inflammation
You may not be aware of certain bad habits that can put unnecessary stress on the body. Wearing high heels is one of them—gulp!—since it puts pressure on the leg joints and lower back. "I'm not against high heels, per se," says Dr. Agus, "but I am against shoes that cause pain. If your feet hurt at the end of the day, that's inflammation." Inflammation has been linked to degenerative diseases such as heart disease, diabetes and cancer, as well as with accelerated aging, so the more of it you avoid, the better. "Listen to your body. If something is hurting, you need to pay attention and figure out a way to eliminate that pain." Chronic gum disease also produces inflammation, so make sure you're flossing on a regular basis.

5. Get your flu shot
This vaccine will not only reduce your risk of getting the flu this season, it can also help prevent the negative long-term effects of the illness. When you're sick with the flu, your body is exposed to intense inflammation—what Dr. Agus describes as an "inflammatory storm"—and that wear-and-tear can have serious future consequences. "One to two weeks with a flu increases lifetime risk for obesity and other illnesses, such as heart disease and cancer," Dr. Agus explains. So protect yourself against influenza by getting vaccinated, or, if you opt not to get the shot, make sure to avoid contact with people who are already sick.