Mostly for the gym because a lot of preworkout breaks fast but black coffee messes up my stomach before the gym
I find the gargoyle staring back at me in the mirror is enough stimulation for me lol.
On a serious note, I think stimulants can impact you differently depending on the length of the fast. I’d experiment with different ones and slowly increasing amounts to make sure it doesn’t adversely impact your health.
I occasionally mix Enduralean with LMNT salts pre workout if I need. Everywhere I looked states 0 cal. It does contain sucralose which is gonna be open for debate, but in a pinch if it’s take that, have a slammin workout and continue not eating ill take that over the alternative. Besides black coffee and black tea I don’t make any other fasting exceptions.