It's been a while since I read his stuff. My son had to go gluten free in 2010 and I did it with him, with good results. That was in terms of allergies and such, rather than weight.
I don't remember Dr. Davis's treatment of carbs in gluten alternatives but I know they are very often pretty high in carbs - even higher than wheat. I think you guessed it with the general rule of no grains at all in lc/keto.