I too am the opposite, I start off reasonably good in the mornings...compared to around 4pm when I start going downhill, ending up pretty awful by the evening. And like you I also put it down to having to eat something, despite being everso strict with what I do eat. A month ago I felt well into the evenings but this last 2 weeks I feel I have gone backwards to how I was when I started the diet last October.
The only thing I have changed is my supplements. Not figured out if its because they are working and getting further die off or because last week (but I did not feel as well before that)I ate some pumpkin seeds as they are supposed to be good for you, and thus discovered I was severely allergic to them, never having had a food allergy in my life ( apart from the obvious gluten allergy from the candida)so I wondered what the hell was going on....vomiting into the gutter in a streetful of people and clinging on to someones parked car because I could not stand up without holding onto something. So maybe I am still recovering from that. I really dont know.