I’m in the same boat – I start work around 0530. I normally have a large breakfast around 7am, eat lunch no later than noon, and when I finish work around 1630, that leaves enough of a gap (i.e. more than four hours) to get some fasted-training effect. I think my calorie intake is significantly higher than yours – breakfast is usually ~900 calories, lunch ~500. I rarely feel hungry before I start exercising ~1630.