Nathanael Johnson is a senior writer at Grist and the author of All Natural: A Skeptic’s Quest to Discover If the Natural Approach to Diet, Childbirth, Healing and the Environment Really Keeps Us Healthier and Happier. He has contributed to magazines such as Harper’s, New York and Conservation, and to National Public Radio and “This American Life.” He writes the “Thought for Food” column at Grist. Follow him on Twitter: @savortooth.