As an emergency room physician, Dr. Travis Stork regularly sees the effects that poor lifestyle choices—the same decisions we face every day about what to eat and how active to be—have on our bodies over time. But just a few small tweaks to your daily habits can help you live longer and feel stronger. You can also conquer many chronic conditions—such as some of the biggest killers in America: heart disease, type II diabetes, and some cancers—before they happen.