When I began this journey, I too had these terrible headaches. I had some stuff left over from having my baby. It was for pain and after four days of a continous headache i took it and was fine after. They since have been farther apart but periodically have them, but yes I believe they are do to my body purging all the toxins stored in the fat that now is being burned. For me i feel when Im getting one it is because my body is releasing a lot of toxins at once. I also believe the better I become at eating all the right food all the time the better i will feel all the time. My blood pressure was a big issue for me. I didnt want to end up on medication and that was where i was headed if I didnt do something. Even as active as I am, I was still suseptable to it because my mom has it and she is thin now but wasnt when she got it. But thinning down wasnt enough. You need to get rid of the junk food too. As soon as I gave it up I could see over time it has come down on a regular basis.