Do we have any idea how the nutrition facts are calculated? Did someone do the testing on some basic foods a long time ago, and then the way those foods are combined, formulas are done, and nutrition facts are estimated? Or is there some body out there that actually throws the food in a blender then runs it through whatever equipment actually burns the food and counts the calories?
And what about the glycemic index? Was there some mass data collection involved there, or is it being estimated based on some formula that extrapolates from a smaller pool of known values?
(i.e.: an apple is tested however they test for the GI value. Then, all other vegetables which share similar nutrition profiles to apples are assumed to have similar GI values, with whatever adjustments for fiber/water content, etc.)
Hell, how is the GI determined to begin wth (I shall consult The Google on that one, seems findable.)