Diet soda vs. water for a workout: And the winner is...

Originally Published: September 27, 1996 - Last Updated / Reviewed On: May 11, 2012
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Dear Alice,

I know that when working out or doing physical activity, you should drink a fair amount of water. I drink a lot of diet soda (used to drink a lot of regular soda), as much as two liters plus in a day. Is diet soda an okay replacement for water? If not, why?

Thanks,
Thirsty

Dear Thirsty,

On your marks, get set, go! Staying hydrated while you’re hitting the gym (or the pavement) is extremely important for an active body. While diet soda may boast zero calories and zero sugar, it is not the Holy Grail to achieving a healthy level of hydration. Diet soda does hydrate the body, but not as well as water. Soaking up the following information can help you stick to water and stay hydrated on the field:

  • Some diet sodas contain caffeine, which has mild diuretic properties and can increase urination. This decreases the amount of water available to the body — quite detrimental if you’re trying to quench your thirst. Caffeine also increases stomach acid levels, which can cause stomach irritation while you are exercising. Lastly, caffeine is addictive and in large quantities can cause insomnia, jitteriness, headaches, anxiety disorders, and fatigue.
  • Diet sodas contain significant amounts of sodium, which draws water out of the body's cells and can contribute to dehydration.
  • Sugary sweet sodas may cause your brain to crave other sweets — not ideal if you’re exercising for health and fitness. In a study done on rodents, artificial sweetener caused the animals to steadily increase their calorie consumption.
  • Both carbonic acid and phosphoric acid are commonly found in sodas. As a result, drinking too much of the bubbly can corrode the enamel of your teeth.

While the FDA has concluded that aspartame is safe for consumption, it has been linked to a number of side effects such as dizziness, migraines, memory loss, diarrhea, and mood swings. If you are concerned about the safety of aspartame, you can always check the labels of the foods and drinks before you buy them. You may also want to consider discussing any concerns with a health care provider, who may be able to suggest other sweetening alternatives. For example, you can give your water a little pizzazz by adding a wedge of lime or lemon.

The bottom line is that water is the best (and cheapest!) hydrator on the market. Moreover, decreasing on your diet soda consumption may be beneficial to your health as well. Check out the related Q&As below for more information. For tips on cutting down, check out Getting off colas, sodas, pop, fiz...oh, whatever! Drink up and keep moving!

Alice