I was under the impression that too much IF (and working out while IFing) could result in lean mass loss due to the body breaking down protein for food.
Am I off-base? Maybe I'm listening to too much bro-science off of the muscle sights? Some go so far as to recommend Casein before bed to avoid this...
I suggest you google Lean Gains. His strategy focuses on the macronutrient ratios in combination with IF. Definitely works.