Do you drink soda? You know you shouldn't right? Oh, what's that? Oh you only drink diet soda because it's a much healthier option...Let's look at the data, then you can decide if it is a healthy option.
1. Havard Medical School did a study of 3,000 women over 11 years. Researchers found that drinking diet soda is associated with risk of delcine in kidney function. Interestingly enough, regular soda didn't cause the same kidney issues as the diet soda.
2. In a 2008 University of Minnesota study of over 10,000 people, researches discovered that drinking just one diet soda per day increases the risk of metabolic syndrome 34%. Metabolic syndrome is a group of symptoms including abdominal fat (belly fat) and high cholesterol which increase the risk of heart disease. 
3. In a University of Texas Health Science Center study it was found that people who drank two or more diet sodas per day increased the size of their waste 500%! That's right, diet soda didn't help them lose weight, it increased their ability to GAIN weight. Here is how: the artificial sweeteners found in diet sodas hinder the body's ability to limit calorie intake based on the sweetness of foods. In other words, because of the unbalance caused, they were inclined to eat more. 
4. For those of you who drink alcohol (which we don't recommend), mixing drinks using diet soda can get you drunker, faster. The Royal Adelaide Hospital in Australia explained in a study that the sugar free ingredients allow the alcohol into the blood stream at a much higher rate than that of sugar.
5. Sodium Benzoate and Potassium Benzoate. These are mold inhibitors (preservatives) found in diet sodas. They are linked to hives, asthma and other allergic reactions. Peter Piper, a professor of molecular biology and biotechnology at the University of Sheffield in the U.K. explains what else they do, "These chemicals have the ability to cause severe damage to DNA in the mitochondria to the point that they totally inactivate it - they knock it out altogether." Destroy mitochondria in our cells! Wait, what does that mean? Mitochondria is the part of the cell that transports oxygen throughout our bodies and those chemicals kill it.
6. Drinking acid because it tastes good...ok diet soda isn't acid but it is very acidic. The pH of diet soda is 3.2. The pH of battery acid is 1 and the pH of water is 7. Drinking multiple sodas a day will put you on a fast track to very poor dental health.
7. Both diet and regular soda are coated with bisphenol A. This is a chemical that disrupts the body's endocrine system and is linked to heart disease, obesity and reproductive problem. It just isn't worth it!
Reference:
http://health.yahoo.net/articles/nutrition/photos/7-side-effects-drinking-diet-soda#0
