>I tried this diet once for two weeks. It definitely works extremely quickly for weight loss, but it would give me a terrible headache everyday so I gave it up.
You weren’t getting enough sodium. Your sodium requirements go up quite a bit on keto and often just extra salting food isn’t enough. When your body can’t enough sodium it can’t manage water in the body, thus leading to headaches from dehydration.
It’s often called the keto flu:
https://www.reddit.com/r/keto/wiki/faq#wiki_what_is_.201Cketo_flu.201D_and_how_long_will_i_have_it.3F
“You weren’t getting enough sodium. Your sodium requirements go up quite a bit on keto and often just extra salting food isn’t enough. When your body can’t enough sodium it can’t manage water in the body, thus leading to headaches from dehydration.”
I seldom if ever have headaces, my wife jokes that I give them to people I don’t like/care for.
When I started my Paleo trip, a friend told me to buy an old fashioned salt grinder and fill it with course pink Himalayan Salt. Keep it where I ate and take it with me when we eat out. If food didn’t taste salty enough to put salt on it. I did and my headaches went away.