Only one out of 500,00 people in America live to age 100. Our bodies are programmed to make it to 90, but the average life expectancy in the U.S. is 78. Why is that? National Geographic writer Dan Buettner studied communities all over the world that have the highest density of centenarians to try to answer that question. In this 20-minute TED Talk, he discusses the habits and diets of golden oldies in, among other places, Sardinia, Okinawa and Loma Linda, California. You may never become a 97-year-old surgeon who performs 20 open-heart operations a month like one of the elders Buettner profiles, but it’s still a worthwhile video to watch.