Does Sugar Make You Thirsty?

A doctor explains how sweets affect your body on a cellular level.

When you eat something sugary, you may notice that you want something to drink afterward. Post-dessert thirst is a common reaction—but why is it that sweet treats make us feel so parched?

To find out, we called Caroline Apovian, MD, a professor in the endocrinology, diabetes, and nutrition department at the Boston University School of Medicine.

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How Are Sugar and Thirst Connected?

The connection between eating sugar and feeling thirsty afterward has to do with a spike in your blood sugar levels. "When you put sugar in your system, it first goes to your stomach, and then into your bloodstream," Dr. Apovian said.

Once the sugar particles reach your blood, water moves out of your cells and into your blood, to restore balance in your blood. As your cells lose water, they send signals to the brain indicating that they need more water. The result is that you feel the urge to sip on something.

"This [chain of events] happens pretty quickly," Dr. Apovian said. "Since glucose is absorbed by the gut and into the bloodstream fairly fast, you might feel thirsty within five or ten minutes." (Any thirst you feel immediately after noshing is likely induced by the act of eating itself, Dr. Apovion pointed out, and not a change in your blood sugar.)

How Can You Solve the Post-Sugar Thirst Issue?

The best way to quench sugar-induced thirst is with a glass of water, Dr. Apovian said, even though you may be craving something sweeter, like juice, lemonade, or hot cocoa. Having a sugary beverage on top of dessert won't do you any good, Dr. Apovian explained: "You're not only confusing your energy balance system by putting more sugar into your body, but also getting a load of empty calories."

When To Be Concerned About Thirstiness

Other reasons for being thirsty might be due to having a very spicy or salty meal or just having participated in rigorous exercise. Additionally, researchers of a June 2021 study published in the Brazilian Journal of Anesthesiology noted that "a long-term interruption in nourishment can decrease gastrointestinal and salivary secretions, increase thirst and mouth dryness and even lead to dehydration." In other words, going without eating or drinking for a long time can lead you to be thirsty as well.

However, if you find yourself being really thirsty—if it's after eating high amounts of sugar or not—it might be due to something else, according to MedlinePlus.

Excessive thirst, known medically as polydipsia, can be one of the symptoms of type 1 or type 2 diabetes. Certain medications, such as diuretics (help get rid of the body's excess water and salt) or demeclocycline (treats some bacterial infections), may also be the cause of your extreme thirstiness. Finally, you could also experience major thirstiness if there are any major losses of fluids (e.g., blood) or failure of the heart, liver, or kidney.

MedlinePlus also mentioned that medical attention may be necessary for the following:

  • continuous thirstiness without cause
  • thirstiness with unexplained symptoms
  • loss of more than 5 quarts of urine daily

Eating sugar can be an enjoyable experience—just make sure you have something nearby in preparation to quench your thirst. But if you still have issues with thirstiness and it's affecting your health, talk to your healthcare provider.

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