Not trying to persuade you to try again, but if you ever desire to, electrolyte deficiency (particularly potassium) is a common reason that people experience he

Not trying to persuade you to try again, but if you ever desire to, electrolyte deficiency (particularly potassium) is a common reason that people experience headaches or cramps when fasting or starting ketogenic diets. Watch out for sugar in commercial electrolyte tablets though!