In the fast-growing field of genetic dieting, the promises of weight loss and better health are many. Here’s how the claims stack up — In stressful times, one of my favorite acts of self-care is to hunker down behind my desk and binge-watch TED Talks, riding the swells of emotional well-being that come along with, say, learning how David Blaine held his breath for 17 minutes underwater, or uncovering the secret power of introverts…