The problem I have with fasting or reducing calories below maintenance is that I have a really hard time focusing mentally on anything. I'm reduced to TV watching. I can't program, study or do any other sort of mental work with any sort of effectiveness. Any suggestions on dealing with this?
Try switching to a ketogenic (ultra low carb / high fat) diet for a week or two beforehand.
The reason you have no focus or energy is due to a lack of glucose (sugar). When you fast your glycogen stores (carbs) will deplete and your body will start running on fat. During the transition, before adjusting, you'll feel slow, weak, and have trouble focusing.
