Plants survive on light and water alone, so why can’t humans? A Seattle woman is putting that question to the test in an “experiment” some find inspiring—though others see it as misguided and dangerous. British-born Naveena Shine, 65, stopped eating on May 3 in to discover whether she could subsist on water, sunlight and tea, and is documenting her efforts on Facebook and YouTube. The extreme fast, which she says she intends to try for “at least 40 days” and perhaps four to six months, is apparently tied to Shine’s New Age beliefs about the universe. Obscure Yogis called “breatharians”...