I did the 8 a.m. to 5 p.m. office thing for about seven years before becoming an academic, and I've almost exclusively taught in the late afternoons or at night since. Something about my Circadian Rhythm makes me want to stay up late and sleep in and has since I was a teen, and I'm productive the most after dark. And, as you say, the more interesting things happen then! The worst side effect is, as you also say, diet, but I'm working on that.