Quite a lot. I was road biking long distances in the summer in the American southeast and replaced all of my table salt with lite salt thinking it would help with recovery. It was 3-4tsp per day, about half in food and half in lemonade. The drink would set me running for the can.
Potassium citrate mixed that with table salt for a recovery drink wound up working really well instead. Based on that, I assumed it was one of the other minerals from the lite salt that was setting me off. Magnesium being the most likely suspect.
Morton's lite salt contains magnesium carbonate, which is an over the counter laxative. I tried using lite salt in lemonade as a sports drink while exercising in really hot weather and the results were... explosive.