Google Image Result for http://www.smallfry.com/wp-content/uploads/2010/04/Lloyds-Body-fat-Monitor-366x243.jpg
When I was a gym member I used to get it measured on a regular basis with their more accurate machine & this one always gave the same results. You do need to use it first thing though as it gives different readings if you use it after eating or drinking. Even though it may not be completely accurate I figure the inaccuracy to any actual figure will be the same all the time so I find it a good way to measure differences even if the actual numbers may be off slightly.
PS: well done on your success with the binging. Having read your journey it seems you are moving forward in the right direction. I think it takes a lot of courage to be as open & honest as you are about your issue & I hope EMF helps you to conquer it once & for all