The National Institutes of Health reports that, though sodium does not contribute calories for weight gain, high doses of sodium will stimulate your body to retain fluids. This is why desert survival protocols include taking salt tablets. Water retention will increase your body weight, but only for as long as you continue to retain the
How Much Weight Can You Gain From Sodium?
The answer depends on your definition of gaining weight. If you mean putting on fat or muscle mass, the answer is zero. Sodium will not contribute to weight gain through added mass. If you're worried about the specific numbers on the scale, such as when cutting weight for an athletic event, then sodium can increase your weight by a few pounds through temporary water retention. The exact amount will vary widely, depending on how much you drink, your total body weight and how much you exercise.