Low Carb Diets reduce the Insulin load on the body. They are also known for requiring more electrolytes. Here’s a study that shows that salt levels are directly impacted by Insulin levels (J Clin Invest. 1975 Apr; 55(4): 845–855. The effect of insulin on renal handling of sodium, potassium, calcium, and phosphate in man. R A DeFronzo, C R Cooke, R Andres, G R Faloona, and P J Davis).
Another related subject (Metabolism. 2011 Jul;60(7):965-8. Low-salt diet increases insulin resistance in healthy subjects. Garg R1, Williams GH, Hurwitz S, Brown NJ, Hopkins PN, Adler GK.)
Low-salt diet was significantly associated with higher homeostasis model assessment index independent of age, sex, blood pressure, body mass index, serum sodium and potassium, serum angiotensin II, plasma renin activity, serum and urine aldosterone, and urine epinephrine and norepinephrine. Low-salt diet is associated with an increase in IR.