I have a hypothesis that all the negative effects associated with increased salt intake are really negative effects of overeating. If we measure the salt intake

I have a hypothesis that all the negative effects associated with increased salt intake are really negative effects of overeating. If we measure the salt intake of people who primarily eat fast food -- which has a constant salt content -- the amount of salt ingested will be proportional to the amount of food ingested. So the person who eats five Big Mac meals a day will ingest, roughly, five times as much salt as a person eating only one, but I would claim the adverse effects associated with this are related to overeating, not the increased salt intake. Is anyone familiar with studies that study the health effects of salt with this in mind? I.e. keeping food amounts constant over different groups, while varying only salt content?