The sneaky reason why people can’t stop drinking soda

Your body tells you to drink when it is time to replenish fluid loss. In fact, studies show the amount of water you typically drink to satisfy thirst matches your deficit in body fluids. Your thirst sensation actually works like a highly accurate water meter. Except in a new study, researchers found this mechanism doesn’t work when you drink sugary water. I’ll explain more about the importance of that finding in a moment. But first, let’s back up.

Hydration doesn’t get much attention from mainstream science. Mainly because the mainstream still doesn’t understand two key features. First, they don’t understand how cells must make their own water for cellular hydration. Second, they don’t understand, how the thirst sensation’s “mechanism of action” really works. In other words, they don’t understand how your thirst sensation works to regulate hydration.

Similarly, mainstream medicine rejects “complementary/alternative” approaches — such as acupuncture — because they don’t understand their mechanisms of action. Even when there’s clear evidence that any natural approach does work, they still reject it because they don’t know how it works.

If we apply the same rationale to hydration, it means doctors shouldn’t recommend drinking water when you feel thirsty because they don’t understand the mechanism of action of thirst! That argument might be hard to swallow — but it uses their same logic.

Your body knows when to stop drinking water

In the new study, researchers used magnetic resonance imaging (MRI) to investigate whether the body inhibits swallowing when you drink more than needed to restore fluid balance.

The researchers observed activity in several areas of the brain: the motor cortex, prefrontal cortices, posterior parietal cortices, striatum, and thalamus. Ratings of swallowing effort correlated to activity in the right prefrontal cortex and vital regions in the brainstem.

They recorded brain responses in these areas at two points. First, when the participants prepared to swallow when they were thirsty. Second, after the participants had drunk enough relative to thirst.

They found participants showed a three-fold increase in the effort to swallow after having drunk sufficient fluids. Overall, the researchers found that the body inhibited the swallow reflex, making it harder to swallow, once the participants had enough water to drink. This effect appears important in regulating overall fluid intake. In other words, it helps make sure you don’t take in more water than your body needs.

Sugary beverages “turn off” body’s natural thirst mechanism

In the next phase of the study, researchers added sucrose (cane sugar, or table sugar) to water, and retested the participants. Amazingly, when participants drank eight-percent sugar water, there was a minimal difference in swallowing effort before or after drinking enough. In other words, the body didn’t inhibit the swallowing reflex after drinking sufficient fluid for hydration. In effect, drinking sugar water seemed to “turn off” the body’s natural thirst-regulation mechanism.

Of course, drinking sugary beverages doesn’t actually satisfy thirst or hydrate your cells. In fact, the sugars dehydrate the body.

But apparently, the sugar can fool the mechanism that controls thirst. That way, you keep drinking more of these unhealthy sugary beverages. In addition, you never become properly hydrated, but you never know it! (How convenient for the soda companies.)

Still think so-called “sports beverages” full of sugar are a good idea for hydration?

Besides throwing off your normal thirst and hydration regulation, sugary beverages (like typical “soft drink” and “sports” beverages) are full of empty calories.

Consuming beverages with artificial sweeteners, instead of sugars, is not the answer either, as I explained last time.

Hydration is important year-round, but it becomes more noticeable as the weather warms up. To stay hydrated at the cellular level, I recommend drinking a cold or hot infusion made with natural constituents like aspal (red bush or rooibos). And when you’ve had enough fluids for proper hydration, your body will know to inhibit your swallowing reflex.



“Overdrinking, swallowing inhibition, and regional brain responses prior to swallowing,” Proc. Natl. Sci. USA, 2016, Oct 25; 113(43): 12274-12279