Lots of well-meaning people are trying to develop systems for labeling foods by their degree of nutritional quality (I file posts on this topic under Scoring systems). My preference is for traffic lights--green for eat anytime, yellow for once-in-a-while, and red for hardly ever). So I was not surprised to see an announcement of a new study from Australia that tested consumers' understanding of several kinds of food ranking systems.
According to the study itself, traffic lights beat out the other systems tested in helping consumers choose healthier foods. I hear rumors that the Institute of Medicine is starting a study to evaluate consumers' understanding of the various kinds of ranking labels on food products. I suppose we will need to wait until that study is complete--a process that usually takes two or three years--before we hear its conclusion. If we have to have one system, I'm voting for traffic lights.