There have been plenty of times when I've used my 30 minute break for sleep and another 15 minutes on the phone calling customers and whatnot (because I can't find the little headset I got as a gift for Fathers Day)...
Seriously though I've found that diet plays a big part in this, and that's where paleo really helped me. Carbs in the morning to crank you metabolism up, and eat light the rest of the day.
It's only when I stray from this path and eat heavy crap during the day that I get groggy now.
Eat a big breakfast, eat light the rest of the day.