Okay, let's not get crazy. Fast food will never be good for you. But that hasn't stopped scientists in Bill Clinton's home state from trying to make it so. Marjorie Fitch-Hilgenberg and Teddy Morelock of the University of Arkansas recently completed a series of unique taste tests among drive-through fans. First they gave 40 subjects three half hamburgerstwo of which contained lettuce and one that had spinach in its place. In fact, no one seemed to notice. "The subjects didn't know what they were tasting for, which part of the sandwich we had changed," Hilgenberg said. But even so, their comments ranged from "too much onion" to "I don't like hamburgers." Very few suspected the fast-food fast one. "Only one or two people mentioned that the lettuce looked very green," she says. "That's as close as they got to guessing."

In follow-up studies, the researchers sneaked spinach into products at two other fast-food chains and came up with the same findings. Given the nutritional value of spinach, the scientists therefore suggest that fast-food chains would do well to adopt their little trick. "We've proven that consumers can't taste the difference between spinach and lettuce in fast food, so there's no reason not to be using it," Hilgenberg notes. There certainly is reason to eat a spinach salad instead of fast food in the first place, but, Hilgenberg adds, "the fact is, people eat it."