You may drink Diet Coke for the energy boost its caffeine provides, but caffeine can cause harm in some cases. A 12-ounce can of Diet Coke contains 47 milligrams of caffeine -- a moderate amount for most people. But if you drink many cans per day, or if you're sensitive to caffeine, you may experience shakiness, dizziness, headaches, anxiety, abnormal heart rhythms and insomnia. Caffeine can also interfere with medications and supplements, including ciprofloxacin, norfloxacin, theophylline and echinacea.
Caffeine affects every individual differently. Generally, the larger a person, the less sensitive he will be to caffeine. If you regularly drink Diet Coke and other caffeinated beverages, you might build up a tolerance, and it will take more and more caffeine to give you the desired boost. On the flip side, if you regularly drink caffeine and then stop, you may experience headaches from withdrawal.
Diet Coke is not a good way to quench your thirst. It is empty of nutritional value and its caffeine content may contribute to dehydration. Caffeine is a diuretic, meaning it makes you urinate. The more Diet Coke you drink, the more you will urinate, sapping the body of needed water. Dehydration can cause dizziness, headaches, speeding heart, seizures and, in extreme cases, death. While drinking caffeinated beverages is unlikely to cause life-threatening dehydration, Diet Coke won't hydrate you nearly as well as water or herbal tea.
You need calcium for growth and maintenance of strong bones and teeth, and Diet Coke may interfere with your calcium levels because it is high in phosphate. Drinking too much Diet Coke adds large amounts of phosphate into the blood stream, which then draws calcium from your bones. Drinking Diet Coke daily may increase your chance of fracture from a fall by three to four times, according an article in the American College of Sports Medicine newsletter. Additionally, too little calcium can cause osteoporosis.
If you choose diet soda to avoid sugar calories or to lose weight, you may be unwittingly hurting your efforts. Behavioral neuroscience Susan E. Swithers explains that people who consume artificially sweetened beverages and eschew sugared beverages have higher body weight and are more likely to have Type 2 diabetes and cardiovascular disease. The reasons aren't clear, but it's possible that sweet, noncaloric foods and drinks throw off the body's natural metabolic responses.
Reactions to Aspartame
When aspartame, the artificial sweetener in Diet Coke, came on the market in the 1980s, there was great public concern that it might cause cancer. These fears appear to be groundless, explains the American Cancer Society explains in a review of aspartame research. However, aspartame can cause other problems. Anyone with phenylketonuria -- a rare disorder in which the body can't process the amino acid phenylalanine -- must avoid aspartame completely. And aspartame may cause minor discomforts -- headaches, digestive distress, mood changes -- in susceptible individuals. If you feel ill after consuming aspartame, check with your health care provider.