Diet Soda: What's Really in That Drink?



Sometimes nothing tastes as good as a soda on a hot summer day, and if you're watching the calories, it's only natural to reach for a diet version.

But some experts say that choice could be doing more harm to your body than good.

"All the ingredients in diet soda are artificially derived," explains Dr. Richard Firshein, founder of The Firshein Center for Comprehensive Medicine. "There is nothing in there your body can utilize.”

Yikes. So what exactly are we drinking when we're sipping diet soda?

Aspartame is the common artificial sweetener used is diet soda and is about 200 times sweeter than table sugar.  “It tricks your brain into thinking it's getting sugar, causing you to crave it more.  This can actually lead to increased appetite, resulting in weight gain,” says Dr. Firshein.  In addition, some people experience adverse side effects including, headaches, dizziness, and joint pain says nutritionist Amy Shapiro.

Phosphoric Acid is what gives soda its bite and tangy flavor.  Evidence provided in a study published in the American Journal of Clinical Nutrition shows a link between the additive and decreased bone density.  “It depletes the body of calcium, weakening bones and teeth,” says Shapiro.  There is also evidence the chemical increases the risk of kidney stones, adds Dr. Firshein.    

Caffeine is the bitter, stimulant found in diet soda.  It impacts the body’s metabolism, giving you a pop of energy, usually followed by a crash.  Too much caffeine can cause restlessness and irritability.  Caffeine is also a diuretic, dehydrating the body, causing you to want to drink more, says Shapiro.  “Caffeine is also extremely addictive, making it harder to kick the diet soda habit,” adds Dr. Firshein. 

Potassium Benzoate is a food preservative that prevents the growth of mold and some bacteria, giving diet soda its long shelf life.  “Anything with ‘benz’ in the name is not good," says Firshein.  "The ingredient becomes highly toxic once broken down in the body to benzene."

Artificial Coloring gives diet soda its caramel color.  “Artificial colors are derived from coal-tar, an oil-based compound.  Many artificial colors have been associated with allergies,” says Dr. Firshein.  They also stain teeth, adds Shapiro.  

In terms of calories, however, at least one expert says it's OK to enjoy a diet soda, as long as you don't overdo it.

“Diet soda, even with its fake sweeteners, is better in a sense because you don’t get the calories you would from regular soda, but only in moderation,” says Michael Jacobson, Executive Director of the Center for Science in the Public Interest. 

Jacobson suggests trying to replace your diet soda all together with something more natural and low-calorie, like sparking water. 

Dr. Firshein adds that adding lemon or lime to sparking water is a great alternative. “I even tell patients to add a little honey for a sweeter taste.  Also, adding berries, melon or cucumber to water or drinking tonic water can be just as good.”