Do Salty Foods Make Us Hungrier?
If you ever downed a high-sodium meal at your favorite restaurant on a Saturday evening out, and then had to reach for a big glass of water (or two) during the night, you may think foods high in salt increase thirst. However, according to a long-term study, salty foods actually decrease thirst—by increasing fluid retention—and boost hunger—by increasing the need for energy.
Research has shown that a high-sodium diet increases urine output. While this was believed to be the result of a higher fluid intake, results of this new study suggest that may not be the case. The study was conducted by an international team of scientists simulating a trip to Mars—a scenario in which the connection between salt intake and drinking could be very important. Two groups of 10 healthy, male volunteers participated in the study—one group was observed for 105 days, the other for more than 205 days. Participants received an identical diet, except they were given three different levels of salt in their food for a period of several weeks.
Results showed that a high-sodium diet caused the men in the study to drink less by triggering a process in the kidneys to conserve fluid. That is, excess salt was removed in the urine while fluid moved back into the kidneys and body. The salty diet also caused the men to feel hungrier—perhaps because of a substance called urea that is formed in the muscles and liver to help the body shed nitrogen. According to researchers, synthesizing urea requires a significant amount of energy.
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