I haven't been on fitday PC in a long time but I think, without context, that they might be referring to calorie balance: calories eaten - calories burned. EXAMPLE: If you need 1200 calories just to live (make new cells, breath, shuttle messages from your brain to other parts), and with your daily life burn another 700 (typing on the computer, fixing coffee, eating lunch, writing your TPA report) and then come home and burn another 300 walking the dog and lifting weights you would have a total calorie requirement of 2200. If you want to gain weight you need to eat more than 2100 calories, if you want to lose weight you need to eat less. So fitday wants to know how many calories you want to restrict from your daily total. So if you need 2200 to maintain and only eat 1700 your calorie restriction is 500.
If I'm remembering correctly fitday asks you to set a calorie restriction goal so you tell it how many fewer calories you want to eat, per day.
no longer morbidly obese: 257 met 10/15/2009
10% loss (27lb):243 met 01/31/2010
no longer severely obese: 224
10% loss (24.3):218.7