I had a revelation at the drug store as I was checking out a package of ethnic-looking cookies at CVS's "food" section. I have never seen Nutrition Information claiming a product to contain trans fat.
When I first heard that food manufacturers would need to start labeling the amount of trans fat in their products, I was thrilled. When the new labels started to appear a year or two ago (though not legally required in the U.S. until January 1st, 2008) I was surprised to find that a number of products I had assumed to contain trans fat (due to their listing of partially hydrogenated oils in their list of ingredients) claimed to have none. Then I learned that food companies were allowed to round down. If the amount of trans fat per serving was less than 0.5 grams, they could label the amount as 0 (while having to advertise as NO TRANS FATS per serving). I thought this was sort of a cheap play, to allow rounding in such a manner (0.49 grams/serving could get away with 0).
According to the FDA (according to Wikipedia), the average American consumes 5.8 grams of trans fat per day (2.6% of calories.) But I bet if you added up the number of grams of trans fat on the labels of everything the average American consumes, you will get a big fat zero. The labeling requirements in Canada allow products with less than 0.2g of trans fat per serving to advertise 0/serving.
Upon realizing that I have never seen anything above 0, it made me wonder whether companies have dropped the amount of hydrogenated oils in their recipes, or whether it has always been the case that labeling the amount of trans fat per serving would always allow it to appear as though there are none. Which makes me wonder what you have to eat in order to see any Nutrition Info change. Because it would be funny if we forced everyone to change their labeling, just so that everyone could label the amount of trans fat as 0.