When we consume a lot of salty foods at once, our brains will secrete ADH, which in turn tells our kidneys to hold onto water, preventing us from peeing out excess fluid. At the same time, the brain secretes another hormone, vasopressin, which is linked to feelings of thirst. Together, all these hormones signal that you need more fluids. Consuming too many salty foods is only an issue if you are also ignoring your thirst cues, Dr. Hew-Butler said.
If you’re looking for savory foods that are hydrating, olives and pickles areacceptable choices, though it’s rare that people consume those in large quantities. Soup, especially with water-based broths, can also help you get your fill of water.
But what is actually dehydrating is alcohol. “Alcohol suppresses ADH,” said Dr. Hyndman. So when you consume it, “you don’t have this hormone telling your kidney to reabsorb water” and any fluids you consume will go straight through you.
Make sure kids, the elderly and those with medical needs get their fill
“Most of us who say we’re dehydrated probably aren’t,” Dr. Hyndman said. While there are probably some people who are walking around a little dehydrated, she added, the majority of folks are adequately hydrated or even a little overhydrated. If you’ve complained of having a small bladder, or you’re just peeing more often than you’d like, maybe you don’t need to be consuming so much fluid — it’s just flowing through you.
Those who need to be most diligent about actively hydrating are children, older adults and people with underlying medical conditions, Dr. Hyndman said.
The rest of us simply need to have a drink or eat foods full of fluids when we are thirsty, Dr. Hew-Butler said, and trust our instincts. “We don’t need to overthink it,” she added.
“I think the ‘drink when you’re thirsty rule’ is one that’s hard to argue against,” Dr. Negoianu said, barring medical conditions or ultra-harsh environments that might cause abnormal water loss. “When it comes to the amount of water you need, it’s like Goldilocks and the Three Bears.” Just as Goldilocks had to decide for herself which porridge was just right, every person has to find the hydration level that’s just right for them and their situation.