Why not feel good all the time? I used to get that, and then I was completely useless at work for the last hour or two. After dinner I was again exhausted, and could barely stay awake until I put the kids to bed at 8.
Since starting the diet, I'm up at 5 and go to bed at 10 or 11, averaging 6 or 7 hours/night. I'd prefer 8. Anyway, I have energy to burn until about 9.
Last weekend I spent the day building a rock retaining wall by myself, played a couple of hours of b-ball and was up at 6 the next morning feeling great. Life is good, and the food tastes great!