I use heavy/double cream (depending on if you’re in the US/UK), Dr Jason Fung says a little bit doesn’t break your fast, since it’s mostly fat. I use about a tablespoon per cup (and drink two cups). I’ve tried it black, even for as long as a month, and I just can’t stand it thay way, and I figure it’s better to fast with just this tiny (very non insulin stimulating) option than to say “oh well, guess I just can’t intermittent fast then”
Short answer - yes it will ruin your fast. No calories during a fast (black coffee) is recommended. Here’s the long answer:
It’s called a dirty fast when you consume less than 50-100 calories during a fast and, yes, it is bad for your fast and not recommended.
The key benefit of fasting is it lowers your insulin levels which causes your body to break down fat instead of glucose for energy. There are more disadvantages than advantages to dirty fasting but the “right” way to do it is to use ingredients that have more fat and next to no carbs, like cream (not milk), MCT oil, or bone broth.
Without going in to overwhelming detail, carbs are what cause insulation production. If you can dirty fast without carbs so you don’t cause a major spike in your insulin levels, it’s less detrimental. I personally wouldn’t recommend it still, but you can as a last resort if it’s what’s going to help you maintain a fast.
At the end of the day, if you burn more calories than you consume, you’re going to lose weight. But you’re just not going to do it at nearly the same rate as others who clean fast and only drink black coffee.
Yes, creamers and milk are breaking your fasting. Anything that causes a spike in insulin will end your fast immediately.Green and black tea are ok too and easier to drink for some without the sugars.Then have coffee with cream etc as soon are your “feed” time begins.
I can’t do black either. I’ve been doing 2 cups with a tablespoon of nut pods creamer in each cup (10 cal/tbsp, no sugar, no carbs). Not sure if it’s ruining my fast; I’ve lost over 15lbs in the past 3 weeks. I’m sure everyone is different though.