An international team of scientists studying the effects of salt intake on our bodies has discovered a surprise: High-salt diets seem to make us less thirsty over time. Reporting in the Journal of Clinical Investigation, they confirm previous findings that more salt makes humans pee more, but added "seemingly counterintuitive" findings that humans on higher-salt diets also consume less water and feel hungrier. The findings, part of the Mars500 project to research space travel, may not only help nutritionists plan what meals astronauts traveling 510 days to Mars and back should eat, but could help us better understand how our bodies achieve homeostasis, or balance, reports USA Today. It seems that bartenders aren't wrong in putting out salty snacks—they make us thirsty in the short term. But after a while, the opposite appears to hold true.
In their study, researchers observed 10 healthy men in a highly controlled environment for 205 days and tested three levels of daily salt intake: 6 grams, 9 grams, and 12 grams, reports the Independent. Over time, the more salt consumed, the less water the men drank and the hungrier they became. So what's going on? The answer apparently revolves around the bodily compound urea. "Its function is to keep water in when our bodies get rid of salt," says one of the researchers. "Nature has apparently found a way to conserve water that would otherwise be carried away into the urine by salt.” But because producing urea is a taxing process that requires energy, it results in feelings of hunger. The latter point was confirmed in a separate but related study of mice, per Popular Science.