I decided to give IF a shot but I’m not sure about caffeine - I wanted to do a 10am-4pm window but I’m wondering if I need to modify that if coffee or red bull would count against me outside of those hours. Any pointers here?
black coffee is basically an essential of this. Adding just about anything to it is a no-no.
To my reckoning, red bull is basically poison. The costs vastly outweigh the benefits. I wouldn’t drink one of those things (anymore) under any circumstances.
Caffeine alone will not affect you e.g. black coffee/pills etc.
Manufactured beverages contain all sorts of other substances than can mess with you- artificial sweeteners and so on.
It’s individual- try it and see.