When you experience muscle cramps on a low carb diet, it is more likely than not a sodium deficiency, not a potassium deficiency. You can get cramps in your jaw, thumbs, calves, rib cage, neck, feet, thighs, etc. Places you did not think could cramp – can and will cramp on a low carb diet from salt deficiency. 2 bouillon cubes a day usually prevents this.