I can give you some clues as to the mechanics of this:
Depleting liver glycogen through diet works for a while to help burn body fat then it stops.
So does depleting muscle glycogen in very short periodic burst of weight lifting but that also stops working.
What is so important to know and I wish I could stress this more is that your body knows what your trying to do it and it just adapts to hold onto its fat reserves. So you have to be gentle with it.
20 grams or less of carbohydrate very long-term is hardcore abuse to your metabolism. (…it may lock itself into storage mode)
A balance between the two (liver & muscle) would be, not to constantly restrict calories.
I found in my own experiments that restricting carbohydrates does no good even up to 300 grams is low. 20 grams is ridiculous long-term and will just make you fatter.