How detrimental to autophagy/ insulin production would 15-25 calories a day be?

I am almost 48 hours into my 7 day fast and read on the wiki that broth is fine to drink during an extended fast.

I currently am allowing myself tea, coffee and water. But I have bullion cubes that clock in at a whole 30 cal a cube. I have divided the cube into 5 cups just for something with a little flavor into my day, as well as sodium. I also chew 2 pieces of gum a day clocking in at 10 cals

I would drink the 5 cups of broth over several days.

Thanks in advance for the responses