Brian proves that muscle and tissue will not disappear the moment one stops training for a bit.
I had to laugh, when I mentioned to my buddy at breakfast last week, how I am taking a week off from training, he said:
"Make sure to keep eating, you shouldn't lose that much if you keep calories high-ish". And this guy's a long time Powerlifter.
I could go on a 7-day water & apple fast, and I won't lose anything in a week. (Some "temp bloat" yes, that's about it).