Just was reading about an article in Business Insider war room....http://www.businessinsider.com/leave-work-early-2011-5 and according to a study by just working harder in short bursts of time you will get more things done! When you are in that zone of focus this is where you try to work hard and deliberately. These focus zones seems to coincide with food. According to its chart there are peaks during lunch hours and dinner hours. By 3pm you are pretty much doodoo.
But for us techies... especially for me, I prefer the geek thrill... trip to Taco Bell with a gulp of Mountain Dew and couple burritoes...I am back in action! Then pizzas for dinner and 7-11 egg sandwich and Monster drinks all the way till 2am!