I'm also having headaches (day 8), but I think after reading this I understand part of the problem. I've been bringing more fruits than vegetables to work for my mid-morning meal (I have breakfast super early so I need something before lunch) and lunch. I also picked up some Rx bars for emergencies like extreme low blood sugar after climbing, but have used them as snacks to get me through until dinner. Today I brought more veggies and haven't eaten a bar so my blood sugar is probably way low after yesterday's spike.
For my meals I've been having: Eggs and a vegetable or fruit (tomatoes,