Diet cola may seem like a sensible alternative to sugar-sweetened sodas, and in some cases it may be. The artificially sweetened beverage contains about 5 calories per 12-ounce can -- compared to 150 calories in the same serving of regular cola -- and no added sugar, making it a seemingly friendly choice for your waistline. That said, diet beverages are not as healthy as good, old-fashioned water, and they may come with some unpleasant side effects.
Diet cola may contain about 35 to 55 milligrams of caffeine per 12 ounces, depending on the brand. Caffeine is a stimulant that can cause side effects such as nervousness, frequent urination, shakiness and irregular heartbeat. If you drink diet cola at night, you may also have trouble sleeping. Most people can safely drink 200 to 300 milligrams of caffeine per day.
A Wider Waistline?
Despite their calorie-free status, diet sodas are linked to weight gain, according to a review published in "Yale Journal of Biology and Medicine" in 2010. Researchers looked at multiple studies and found that participants who drank the most diet soda were most likely to gain weight over time. They also noted that as diet soda use has increased in the general population, so has the obesity rate. This could be because the artificial sweeteners in diet sodas only partially activate food-reward pathways in the brain, encouraging further food-seeking behavior. In addition, artificial sweeteners -- which are far sweeter than natural sugar -- train the brain to crave sweet food, possibly increasing overall sugar intake.
All colas contain acid, which is bad news for your smile. These acids contribute to plaque formation and also soften your teeth's protective enamel coating. This may encourage cavities and tooth decay and cause sensitive teeth or pain while eating. To help preserve your oral health, only drink diet cola through a straw, which will minimize the liquid's contact with your teeth.
The Aspartame Question
Diet colas are often sweetened with aspartame, a controversial ingredient. Although aspartame is approved by the U.S. Food and Drug Administration and generally considered safe, some people have reported side effects such as headaches, seizures and behavioral changes, according to The University of Arizona Cooperative Extension. However, no clear link to these effects has been established. In addition, the sweetener is not safe for people with a medical condition called phenylketonuria, which prevents the body from breaking down phenylalanine, an amino acid in aspartame. Sucralose, another artificial sweetener common in diet colas, has not been found to produce any negative effects.