Two weeks ago I wrote a post about the mistake we make when we think of some medicine or food as generally “good for you” or “bad for you” as opposed to having specific benefits and harms.  I started with an anecdote in which a friend asked me whether diet sodas or regular sodas were better for you. Susan Dopart, a terrific dietitian who I’ve known for over a decade, emailed me to bend my thinking about diet sodas and about non-nutritive...