We've been told for decades to hold the salt at the dinner table for the sake of our hearts and blood pressure. The anti-salt campaign has blurred the picture about what salt actually does for us—besides making everything taste better. Salt is an essential mineral that has many vital functions in the body, which I go into more in my new book, The Salt Fix. Since we lose salt every day through sweat and urine, we need to consume some salt in order to live.
What happens when we aren't getting the salt we need?
When our bodies become depleted in salt, the brain seems to react by sensitizing the reward system—and not just the reward system for salt, but the same reward system that drives us to other pleasurable activities. The purpose of that sensitization is that when we eat salt it induces a greater reward than usual, leading to an increase intake of salt. This primitive "reptilian" response in the brain is over 100 million years old and it has carried over from our ancient ancestors. Its goal is to keep us alive by preventing or quickly fixing a salt deficit in the body. In other words, the brain controls our salt fix.
In our modern world, though, this reward system, intended to save our lives after salt deficit, could be inadvertently leading to weight gain, and even obesity.
How? For starters, following the low-salt advice only increases your risk of salt depletion and hence a hyperactive reward system in the brain. During ancient times we weren’t surrounded by hyper-palatable foods. However, this sensitized reward system can be "hijacked" by our current food environment. For example, if you are following the low-salt advice and you have a hyperactive reward system in the brain, that piece of chocolate cake or candy bar may provide an enhanced reward, leading to an increased consumption of sweets. In other words, low-salt diets may increase your risk of becoming hooked on sugary foods, which predispose you to weight gain.
Another possible way a low-salt diet can lead to weight gain is by increasing the amount of sugar in the foods you consume. Salt not only adds flavor to your food but also sweetness, as it takes the bitterness out of food. When we take the salt out of our cooking, we have to replace it with something. That something generally turns out to be sugar. The low-salt advice may be why approximately 75 percent of all packaged foods in the United States contain added sugars. And a higher intake of refined sugar is associated with an increased risk of weight gain or obesity. This may explain why the high-salt-, low-sugar-eating Japanese have one-tenth the obesity rates of the United States.
A third way that a low-salt diet may predispose us to obesity is through an increased consumption of refined carbohydrates. There is an inherent drive for humans to consume around 3,000 to 4,000 mg of sodium every day. The widespread use of "low-salt" versions of foods scattered across the grocery aisles does not fully satisfy our salt penchant. So instead of eating one bag of salty chips or popcorn, you may end up eating three bags of the "low-salt" versions to obtain the salt your body desires. In other words, low-salt foods may mean a greater intake of chips, popcorn, or pretzels, for example, predisposing us to weight gain.
A final way that a low-salt diet may pack on the pounds is how it affects the fat-storing hormone insulin. Since insulin also helps the body to retain more salt, low-salt diets can increase insulin levels, potentially increasing the amount of fat you store with each calorie you consume. Low-salt diets have also been found to promote insulin resistance and may even double the absorption of dietary fat in the diet.
Eating the salt your body craves may be an easy strategy to also reduce your intake of, and perhaps even desire for, sugar and refined carbohydrates.
Consuming a normal salt diet (around one and a half teaspoons of salt per day) may also help to keep your insulin levels low. Thus, adding more salt to your diet could be a solution for healthy weight loss. Also consider that salt allows bitter foods such as nuts, seeds, and vegetables to taste sweeter. It’ll help you to eat more of these healthy foods. So for the sake of our waistlines, don’t fear the salt shaker. Instead, fear the other white crystal: sugar. The secret to health is simple: Eat real food and salt to taste.