I believe the yields are the part you actually eat, so you could weigh an apple and enter it in as raw yields, or if you want to weigh it the other way, you would weigh it, eat it, then weigh and subtract the portion you didn't eat (the core) and this would be oz.
I just weight everything raw and use the plain oz label. If its a banana I weigh it without the peal, if its a plum I weigh it then subtract the core. But I'm pretty sure the oz yields subtracts a minor amount of calories.
Be careful with your meats, I suggest always weighing them raw, because the different designations of fitday change the calorie content a lot.
It's lack of faith that makes people afraid of meeting challenges, and I believed in myself. ~Muhammad Ali
You must have long-range goals to keep you from being frustrated by short-range failures. ~Charles C. Noble
July 6th 2010: 225 lbs, 24% body fat
Nov 30th 2010: 181 lbs, 12% body fat
Dec 28th 2010: 177 lbs, 11% bf
Total weight loss 48 lbs.