How to Die Young at a Ripe Old Age. by Dr. Steven R Gundry. In The Longevity Paradox, he maps out a new approach to aging well—one that is based on supporting the health of the “oldest” parts of us: the microorganisms that live within our bodies. Our gut bugs—the bacteria that make up the microbiome—largely determine our health over the years. From diseases like cancer and Alzheimer’s to common ailments like arthritis and the appearance of our skin, these bugs are in the driver’s seat, controlling our quality of life as we age.