The Doctors Eades (authors of Protein Power) suggest supplementing with 400mg potassium when commencing a low carb eating plan.

Do take potassium tablets with food, as they can upset your stomach. And as Talon says, check with your doctor or pharmacist if taking fluid or BP tabs (some of those are potassium sparing, so it could be dangerous to take added potassium).

Also do make sure you are drinking plenty of water.

I must mention however, that magnesium prevents cramps. It is best absorbed when taken with calcium in a 2cal:1mag combination. We need 1000:500mg daily - in divided doses.

Cheers.

Rosebud