food sensitivities testing

I recently underwent a food sensitivities screening with my naturopath using a VEGA machine. Basically, your body is put into the same electrical circuit as a variety of different foods and chemicals, and then your body's energy levels are tested in response to each substance. But the foods never actually come into contact with your body. Has anyone ever heard of this? I tested sensitive to all dairy products, wheat, sugar, corn syrup, molassas, corn, rye, potatoes, and barley. I do notice that if I avoid some of these things, my digestive symptoms improve. But I still don't understand how the test can actually work. I kind of think that these are foods that might affect ANYONE negatively (especially the sugar, wheat, and dairy), so perhaps that's why I seem to get a positive effect from eliminating them. Has anyone ever taken a test like this? What were your experiences with it? Thanks!