I am doing basically IF now and it's working fine. Metabolism confusion I have never heard of, but I am skeptical of any sort of 'confusion' when it comes to working out or nutrition. Muscles are basically binary, and metabolisms are easy to get predictable results out of, once you find out how yours works.
I say 'basically' IF because I will have a 100cal yogurt as a snack at 11am, two 100cal yogurts post workout at 2pm, and then 1200cal dinner, and 200cal evening protein shake.
so for example, last night for dinner was 19oz of ground beef, 2 cups of corn, and a banana for dessert. nommm