Diabetes and Preventing Dehydration

by Grace Rivers, RDN, CDCES

When you have diabetes and your blood sugar goes above a healthy range, your kidneys filter and remove the excess sugar. In the process, you start to lose too much water and feel thirsty. Your response? You drink more.

It’s a vicious cycle until your blood sugar gets under control.

Symptoms of dehydration:

When you lose more liquid than you consume and cannot carry out typical body tasks, you may experience:




Rapid heartbeat

Dry eyes or mouth


Dark urine


How much liquid do you need?

The human adult body consists of 47-59% water. The daily Adequate Intake from the Institutes of Medicine is 2.7 liters for women and 3.7 liters for men. That amount translates to roughly 90 ounces or 11 eight-ounce glasses for women and 123 ounces or 15 eight-ounce glasses for men. These amounts may seem enormous, but keep in mind that we consume water through the foods we eat.

Choose fruits and veggies to help increase your water intake. The water content of fruits and veggies ranges from 79-96%, and if dried, fruit is only 31% water.

What does it mean to be well-hydrated?

When well-hydrated, your body can function at its best in carrying out many functions such as:

Transporting food through your gut

Managing your blood sugar

Quenching your thirst

Cushioning your joints

Regulating your body temperature

Moisturizing your mouth, ears, nose, and throat

Keep liquids handy

Have liquids available no matter your location as much as possible. Using a reusable container or bottled water helps.

Best liquids that can help you stay hydrated


Flavored non-caloric water

Sparkling water without added sugar, ready to drink or homemade

Diet drinks

Unsweetened coffee or tea

Worst liquids

Sugar-sweetened beverages

Energy drinks or shots

Fruit juices


Be aware of your caffeine intake

Drinking caffeinated beverages doesn’t cause dehydration if done so in moderate amounts. In healthy individuals, the amount of fluid lost through urine is no more than the quantity of caffeine consumed. Not everyone tolerates caffeine the same, but the FDA cites 400 mg of caffeine a day as safe for most healthy adults.

An 8-ounce cup of coffee furnishes an average of 100mg. You may also get caffeine from other liquids such as energy shots as well as some foods.

If you struggle with high blood sugars, decreasing your caffeine intake may help. One review of studies found that caffeine ingestion did cause higher blood sugar levels and extended it for a longer time. The review also noted that further research is needed.

Water pills and dehydration

Taking a water pill (diuretic) is a common medication for controlling blood pressure. Diuretics assist your kidneys in getting rid of excess sodium. Water travels with the sodium causing you to urinate. Staying hydrated is necessary for the water pill to be effective and to prevent dehydration. Inform your doctor if you notice signs that you may be dehydrated that aren’t remedied by increasing water intake.  

When more liquid is needed

When exercising, vomiting, or having a fever or diarrhea, consume extra water to stay well-hydrated.

Hydration is key all year long

Keeping hydration top of mind is essential to staying well-hydrated during all four seasons. Even though we sweat more in the warmer months, we still lose water (vapor) daily with breathing. Heating and cooling systems can also have a drying effect. If you experience dehydration with controlled blood sugars and your symptoms aren’t easily fixed with increased liquid intake, discuss this with your doctor.

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