Absolutely. I really started noticing this in the summer (after about 3 months on the diet). I found myself clearing my desk at work in no time at all and making much quicker decisions. By early afternoon, I'm often out of stuff to do! I'm normally an avid reader but this past summer, I took it to a new level. I read some 15 books over the summer (not including the diet books that I devoured in the spring) and I have both papers read in the morning before I even go to work (and after my morning walk).
My energy level with this plan is enormous. Even though I get up at 5AM, I still go to bed around 10 to 10:30. But once I go to bed, I'm out like a light. No more problems with insomnia. In fact, I have had the most vivid dreams. I really should start recording them.