What is the impact of electrolyte intake on weight loss?

Question

A few years ago, the National Institutes of Health released a weight loss calculator based on a number of studies, supposedly allowing one to plug in a number of body and lifestyle factors, such as height, weight, age, body fat percentage, caloric intake, percentage of intake from carbohydrates, and so on, and predict weight loss rates given specified changes.

I was playing around with this calculator, and found a really interesting result: decreasing the sodium intake from the default (4000mg/day) greatly increases the caloric deficit needed to achieve the same level of weight loss in the same time. Conversely, increasing the sodium intake decreases the necessary caloric intake, in theory allowing for quicker weight loss.

Is the result implied by this NIH weight loss calculator, that higher sodium intake increases weight loss per caloric deficit, supported by scientific evidence, and is this also true for other electrolytes?

Answer 1

You asked for any evidence, and we have this paper, Increased salt consumption induces body water conservation and decreases fluid intake which is interpreted in this newspaper article.

Essentially, a higher salt intake does not induce a corresponding increase in free water intake. But renal excretion of water still continues at a rate higher than that imbibed. Which meant that the missing water excreted had to come from metabolic breakdown of fat and muscle using increased glucocorticoid production. This leads to weight loss. But increased endogenous release of glucocorticoids also has adverse health implications eg. osteoporosis, and sarcopaenia.