Headaches from stored toxins?

Starting the 40 days at Monday, May 4 with 5 days of BPIF I lost 1½ kg of weight. Friday evening I was completely foggy in my brain; constantly forgetting what I was doing and almost placing the wrong things in the fridge. After that followed 2 days of constant headaches, that continued around the nights until yesterday morning. It seemed to take a break when I got my butter-coffee in the morning, and the weight loss continued.

My guess is that I've started burning stored fat and thereby releasing stored toxins. Otherwise I don't really know how to interpret this.

About the gluten, I don't feel any craving for it at all. That might be my decision to not regard it as food for these 40 days, or it might be that I don't have any gluteomorphin cleansing to speak of.

Just to make it clear: I'm not following the Bulletproof Diet outside the intermittent fasting. To avoid gluten I bring all my lunch to work, so it is good organic food. Sometimes the lunches are low carb, but they might as well be with e.g. rice. Cooking all my meals and breaking the habits of pasta/pizza/… having a focus on food that's good for me, rather than what I like is one of the side effects that makes these weeks so much more than just skipping gluten.