Giving fat as percent of total calories, for instance, means nothing in itself. It is the proportion of total daily energy as fat from the entire day's food intake which is relevant. Some foods are naturally high in sucrose, which is no different from added sucrose. It is often impossible to guarantee that a food does not contain traces of nuts protein, even although nuts are not an ingredient. It is usually the RDA for an adult male, but the values could be quite erroneous if the consumer is an adult female, pregnant, a little old lady or a child of six.
Adult males are a minority of the population.
There is a real danger of getting altogether too clever over food labels. There is an urgent need to define a minimum list of required declarations, and keep all other information for leaflets, web pages or phone enquiries. Every two years the US National Science Foundation surveys Americans' understanding of science. The results of the 1999 survey are not encouraging. How such people can be involved meaningfully in debates about genetic engineering or advances using the human genome information is very doubtful as they cannot grasp the underlying principles.