serving size

I had noticed the thiner bread slices in breads that claim to have fewer calories per slice but I hadn't thought of serving size reduction, to below a threshold that can be claimed zero, as a general "cheat method" in advertising. Look at this: Coffee creamers, for example, may contain 30% or 40% fat, but by defining the serving size as one teaspoon, the manufacturer may claim that one serving has zero fat, even though one teaspoon may not be a sufficient amount to whiten a cup of coffee.