Not sure what your purpose in fasting is, but if it is to lose body fat & therefore detox and if you don't want to lose muscle mass, make it a protein-modified fast by adding in some lean meat. Gentle walking for 20-30 min daily.

I did GAPS and I must say broth is not enough to survive on, at least wasn't for me, and I think it just made me hungrier as I was constantly drinking and wanted to eat.

If you are adding carbs to it I'm not sure its considered a fast?? If you aren't opposed to adding things try egg yolks or mashed up avocado. adds a bit more substance to it.

The question I have is why just a bone broth fast?. My current protocol is itermitant fasting: bulletproof type coffe, (my own version with added 100% bakers chocolate melted and mixed in with cocnut oil and butter), 2 cups of bone broth around 1:00, followed by my first meal around 2:00 and then dinner around 6:00 and maybe a banana at 8:00. I have been doing this for a week with decent results. I've been LC paleo for over a year and stalled, this seems to be moving things along so far.

Adding carbs isn't likely to help. The point of a fast is that your body has to use what it has stored. If you give it too much support it gets confused and instead relies on you to feed it. I don't know how I'd do on a broth fast, it's easier just with water, but I'd suggest concentrating your broth into one meal a day and stick to non-caloric drinks the rest of the time and let your digestive system rest. Once you get used to it it'll stop pestering you so much.

If you need something to get your mind off hunger, some good strong ginger tea will do the trick. It is also good for your digestive system. I like Traditional Medicinals, brewed for a long time.

Get through the first couple days without giving in and you'll be fine. I agree with PrimalDanny though.