I don't know if there is an official time in between meals to qualify as a fast but I consider anything longer than 16 hours without a significant caloric intake as a fast.
F 28/5'4/100 lbs
"I'm not a psychopath, I'm a high-functioning sociopath; do your research."
i don't think there is an actual minimum, but i do think it sounds strange when people say something like "i took a 4 hour fast today"-- when the time is very short it doesn't sound like the appropriate word. i guess i'm kind of old-fashioned on that, though, when i think of fasting i think of bible characters out in the desert, etc. i probably wouldn't use the term for anything shy of 20 hours or so unless i was specifically referencing an eating regimen like "i'm going to do LeanGains, and my fasting window will be 16/8 from x time to y time fasting" where the term is part of the plan's language.
in all seriousness, though, it's not the word you use that matters, but the effect on your body. you can take a "38.5 minute fast" and it will be clear to anyone what you mean and to you what the effects are , even if it sounds silly on teh forums (what doesn't?).
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