Even the simplest information — a red, yellow or green “traffic light,” for example — would encourage consumers to make healthier choices. That might help counter obesity, a problem all but the most cynical agree is closely related to the consumption of junk food.

Of course, labeling changes like this would bring cries of hysteria from the food producers who argue that all foods are fine, although some should be eaten in moderation. To them, a red traffic-light symbol on chips and soda might as well be a skull and crossbones. But traffic lights could work: indeed, in one study, sales of red-lighted soda fell by 16.5 percent in three months…

Every packaged food label would feature a color-coded bar with a 15-point scale so that almost instantly the consumer could determine whether the product’s overall rating fell between 11 and 15 (green), 6 and 10 (yellow) or 0 and 5 (red). This alone could be enough for a fair snap decision. (We’ve also got a box to indicate the presence or absence of G.M.O.’s.)