Well, I'm not sure if it was intermittent fasting medical journal articles or Ori Hofmekler's book "Warrior Diet". Seems like something Ori would say, I'll take a look this weekend if I find a quote and I'll pass it along.

The other reality is IF-ing make you a little blase about your workout. I've been known to yawn during a "hi intensity" workout, more interested in girls walking by then blasting out a set or aggressively spinning up a climb. That might be consistent with your statement that it's a low octane fuel you're burning.