We make a lot of claims about how what we eat affects how we live, and how healthy we feel. But scientifically proving the links between diet and disease is complicated—especially when patients face many uphill battles that are seemingly unrelated to their condition. For my latest for NPR’s The Salt, I explore the challenges of setting up a study of heart failure patients learning to cook—possibly for the first time—and whether changes to their diet may help keep them out of the hospital.