How Do People Count?

My recent labelling post caused quite a debate and got me thinking about dieting and whether people focus on what's good for them or count up the bad things they can get away with eating each day.

I don't know tha answer, but it suggests to me that you really need to know how the people in your marketplace are thinking. Are they focussing on what's good for them i.e. quality or do they know that their choices aren't the best but they figure they can get away with a certain consumption level without having a negative outcome?