Too Much Salt Makes Us Eat More and Drink Less

Salty food makes us thirsty in the short term, but in the long run, a high-salt diet doesn’t cause people to drink more fluids.

During a simulated mission to Mars, researchers looked at how a high-salt diet impacted drinking habits. The pair of studies found that a high-salt diet doesn’t make you drink more in the long-term. Instead, you retain water, and you end up eating more, but drinking less.

THE SALT STUDIES

In the first study, two groups of 10 cosmonauts each went on a simulated mission to Mars. The first group’s mission was 105 days, and the second group’s was 205 days. Both groups ate the exact same foods, but researchers changed the amount of salt in their meals for several weeks at a time. 

The second study examined why cosmonauts were drinking less and eating more. To figure that out, they looked at how mice handle a high-salt diet over time. It turns out that the cosmonauts in the study ate more because a high-salt diet increased their caloric needs. That’s because eating more salt causes more urea to accumulate in our kidneys. Our bodies have to produce that extra urea, and that takes more energy.

WHAT WAS HAPPENING?

The researchers believe that we produce more urea when we eat more salt as a defense mechanism. The urea helps our bodies hang onto water while still getting rid of excess salt.

Prof. Friedrich C. Luft explains in a press release, ”Nature has apparently found a way to conserve water that would otherwise be carried away into the urine by salt.”

SALT AND OUR HEALTH

What the study did not look at is how the high-salt diets impacted other health factors, like blood pressure or heart health. Our bodies need some sodium to function properly, but high-salt diets are associated with health problems like cardiovascular disease and kidney damage.

While there is not a total consensus on how much salt we should eat per day, the maximum amount falls between 1500 mg and 2300 mg per day, depending on your age and health.

If you have high blood pressure, heart disease or other health issues, you should stick to 1500 mg per day or less. For healthy people ages 14 and older, 2300 mg per day is the maximum amount of salt we should be eating. That’s between 3/4 teaspoon and a teaspoon daily.

Most Americans eat far more than that. In fact, the average American eats 3400 mg per day.