Josie Porter is always reassessing her supplement stack. The dietitian and author of "How Not To Take Supplements," which promotes a food-first approach to health, takes them as needed. That's why she stopped taking creatine around three years, when she started going to the gym less around a year ago. Creatine, once a secret weapon of athletes and bodybuilders, has gone mainstream in recent years as strength training has overtaken cardio as the workout du jour. The body naturally produces