If you are trying to get it down to an exact is to get a food scale. Try testing your calorie intake for a couple weeks while uploading the information. Weigh yourself when you wake up after a bowel movement at the beginning and at the end. If you are at the same weight cut calories off of what you have been eating. If you go up cut more. If you lose weight, then you are headed in the right direction.
Also, pork screws... are you eating dog treats?