Ever eat a bag of chips or a bunch of mozzarella sticks, only to look down and realize your fingers have swollen to twice their normal size? It’s not your imagination — your fingers really are getting larger. One of the many side effects of eating excess sodium is that your body puffs up, and the effect is most noticeable in extremities such as your fingers and toes.
Here’s why this happens. When you eat something filled with sodium, the sodium enters your bloodstream. According to the National Institutes of Health, your body typically maintains its balance of salt and fluids by sustaining a certain ratio of sodium and water in the bloodstream. Sodium is excreted through urine via the kidneys — so you have to pee in order to release the excess sodium. However, your body can also retain fluid, and when there is excess sodium in your bloodstream, there ends up being larger amounts of water in your bloodstream, as well.
When there is too much sodium in your bloodstream, your brain triggers thirst and you’re likely to drink more water. If you don’t drink enough water to even out the sodium concentrations in your blood, however, or if you drink a beverage that contains more sodium, such as soda (which can contain around 30 to 40 milligrams of sodium per 12-ounce can), your body draws water out of its cells in order to get more fluids. Either way, your body figures out how to get more water into your bloodstream, increasing the volume of your blood vessels.
Increased blood vessel volume has a couple of consequences. First, you’re going to puff up. Your body is literally more voluminous, and this results in what’s often called “water weight.” Increased blood volume also puts more stress on the walls of your arteries, increasing your blood pressure. It’s believed that this causes strain on your arteries and your heart, and is a large reason why the American Heart Association warns against eating foods with too much sodium.
As your kidneys excrete sodium from your system, the swelling goes down — unless, of course, you keep eating more salt. But until your kidneys finish their job, you’re also likely to experience these other effects of eating too much salt.