Per hundred grams is comparable and per serving is not
Why per serving misleads
A serving might be a third of the packet or the whole thing. Two similar products can have serving sizes differing by three times.
The traffic lights
Useful and based on per-hundred-gram figures. Red for anything is not a prohibition; it is a prompt to consider how much you eat.
The one to watch
Salt, which is listed rather than sodium in most places now. Six grams a day is the guideline and most people are well above it.
