Excess Salt May Make You Hungrier
What to Know
Salt improves the flavor of food, but most Americans eat too much of it. That puts their health at risk. Excessive salt contributes to high blood pressure, heart disease, and kidney failure, all of which are common complications of diabetes. Now research suggests that salt may play a previously unknown role in our health: It may trigger hunger.
Over several months, German and American researchers put 10 male Russian astronauts on a series of three diets, each of which lasted several weeks and differed in only one key way: the amount of added salt. The astronauts, taking part in a months-long training exercise meant to simulate a space flight to Mars, first ate 12 grams of salt per day. Next, their daily diet contained 9 grams. Finally, their salt intake dropped to 6 grams per day. That’s equivalent to U.S. Department of Agriculture (USDA) guidelines for daily salt consumption. The researchers monitored how much the astronauts drank on the different diets and analyzed their urine to determine how much sodium they excreted.
The researchers reported two unexpected outcomes. First, excess salt did not boost the astronauts’ thirst; in fact, they drank less water while on the high-salt diet. They also complained that they were hungry when their meals contained more salt. The researchers did a second study, this one on mice, to learn what might cause that hunger. When the mice ate large amounts of salt, they drank less water than expected, so their bodies had to produce more water to keep a healthy balance of salt to water. That process requires lots of energy, or calories, which may explain the hunger the astronauts experienced. Without enough calories, the body will break down muscle to fuel water production.
Excess salt may make you hungrier by using up calories to produce water. But instead of helping you lose weight, the process can prime you for hunger, causing you to overeat and, over time, gain weight. Much more research needs to be done to confirm this previously unknown effect. Right now, it’s just a theory. Nevertheless, it’s clear that limiting salt helps maintain good health. The American Diabetes Association recommends no more than 2,300 milligrams of sodium per day for most adults.
“Increased salt consumption induces body water conservation and decreases fluid intake.”Natalia Rakova, Kento Kitada, Kathrin Lerchl, Anke Dahlmann, Anna Birukov, Steffen Daub, Christoph Kopp, Tetyana Pedchenko, Yahua Zhang, Luis Beck, Bernd Johannes, Adriana Marton, Dominik N. Müller, Manfred Rauh, Friedrich C. Luft, and Jens Titze. Journal of Clinical Investigation, April 17, 2017; 122(5): 1932-1943.