Thanks for helping out @kremik13!
Flow contains a - very little - amount of calories, indeed. 23 per serving to be exact.
Still, as mentioned before: it's a supplement. That's why, personally, I wouldn't consider it "food" or "eating".
But I guess you would have to decide upon that yourself @hoaza...
Either way: I'm not really familiar with the topic of Intermittent Fasting myself, so I'm sorry for any miscommunications or misunderstanding!