Thinking about playing with IF again, but wondering about drinking broth. If skimmed of fat, would that be ok to sip on or would it break the fast? I don't do black coffee, and it would be nice to still have my hot drink in the morning!
It depends on why you're fasting. I fast mostly as a way of controlling calories and in that case, the little bit of carbs and protein in broth won't make a big difference.
Other folks do IF for the benefits of fasting-induced autophagy. Folks who do this type of fast (like Paul Jaminet) often will eat coconut oil during their "fast" as it provides easy energy for the brain, allowing them to extend the protein fast.
Others are more orthodox and figure fasting means fasting. So the answer is, it depends ;).
EDIT: Sorry, I just noticed your comment about autophagy - if you're doing this for weight loss, starving yourself slows down the metabolism, something the body does to keep from wasting away. So when you start eating again, the body is going to pack it on, fearing another famine. I thought the point of IF was for health benefits, not weight loss. For weight loss, I recommend doing a good old fashioned leptin reset. Your weight should take care of itself, if you take care of your body. We become healthy to lose weight, not lose weight to become healthy. [end of edit.]
I personally fast for the healing effect it has. I consume calories during it, for sure. When I was low carb (had not yet discovered paleo or leptin imbalance - derp!), I used to do a fast on master cleanser with just a lime (less carby than lemon) and hot water with cayenne and ginger, which really get the acids moving. Then when I got hungry I would kick back some shots of raw, organic, cold pressed extra virgin coconut oil or have some organic veggie juice.
And now that I have a juicer, I'm juicing high-nutrient kale and things that detoxify you like cilantro (helps with heavy metals) - and the formula I'm using right now is going to eat away at my phytoestrogens and detox me from heavy metals and nourish me, give me energy, detox my liver and gut, and I break the fast every night with a healthy dinner (usually steak - I want my meaty nutrients, too!). I've done this for two weeks and I feel great!
I also use my blender to juice up a healthy fruit protein shake - Whey powder from New Zealand (grass fed cows), some strawberries and blueberries, chlorella, spirulina, aloe vera gel, apple cider vinegar with mother (you can't taste it blended in with everything else), l-glutamine (heals the gut), and vitamin C crystals (about 1500mg worth of vitamin C).
I also did a vitamin C flush last weekend - no regrets, man. I used a teaspoon of vitamin C crystals every fifteen minutes with half a glass of water in the morning on an empty stomach and continue until I get the runs - this flush is great because it not only helps to detox the colon and everything, but it clears up the lymph vessels in the colon as well. So I felt great after that.
So I don't really care about how many calories I consume during the fast - as long as I'm not being ridiculous - and as long as there is no solid food coming in, the GI system has a chance to rest and the body has a chance to catch up on its list of chores - usually when done for longer periods. With IF, I tend to eat at night, or whenever I become hungry in the afternoon.
Bone broths provide a lot of good stuff for us. It's mostly water, so the calories will be very low. There's some aminos there, mostly glycine - if you mean bone broth and not meat broth, but shouldn't be enough to kick you out of ketosis or ruin your fast.
I do a 16 hour IF several times a week, sometimes for a whole week, sometimes only once and I use coconut oil in coffee so I stay alert as I need my brain for my job. In your case, feel free to add coconut oil to the broth.
As long as the whole thing is not too calorie dense, it should be fine. If there's a lot of protein in there, you'll trigger an insulin response, but I doubt it:
One cup of off the shelf beef broth has 1g carbs, and 2g of protein. So 12 calories. What you make at home will vary of course, but it'll be tastier and healthier. :)
I would say that this is okay on a fast. You'd probably get the superb gut-healing benefits as well, since the broth would have no interference from other foods/drinks. Martin Berkham of Leangains (intermittent fasting) has participated in coffee + 1 tbsp of cream during his fasting window. I'd say coffee has minerals as well, so this may be an analogous experience.
But like Beth said, it can depend- if you drink an entire gallon, then obviously you're "breaking your fast." A cup or two? No worries.
Nourished Kitchens also talks about what's IN bone broth: http://nourishedkitchen.com/the-benefits-of-bone-broth/
I think you're good to go!
What about tea? I've really grown fond of green tea, and it also helps blunt any appetite issues.
ETA: For fat loss, I think you'll get too much nutrition out of broth and it's likely to break your fast.