How do you count calories when juicing?

arotella

My power juicer just arrived in the mail (YAY!) and I would like to start incorporating fruit/veggie juice in my daily diet starting today. Question is, how do I count these calories? Obviously eating one whole apple will be more calories than simply drinking the juice from the apple.
I found an article at Ehow.com (http://www.ehow.com/how_5155227_count-calories-juicing.html) stating you should multiply the number of fiber by 4 (since 1 gram of fiber = 4 calories) and subtract that number from the total amount of calories in the food. That's my plan for now, but I am wondering how accurate this article is. Any suggestions or experience with this?

BTW... I checked and there are some "fresh juice" options in MFP's database, but I don't 100% trust that it was added in correctly. I prefer to double check the math!

Thanks!