Some harmful side effects of diet soda may include metabolic syndrome, depression and the increased chance of developing Type 2 diabetes. Metabolic syndrome refers a list of risk factors; if an individual displays three or more of these factors, he may be diagnosed with metabolic syndrome.
The risk factors for metabolic syndrome are abdominal obesity, high fasting glucose, high triglycerides, high cholesterol and high blood pressure. A study by the American Heart Association followed over 9,000 individuals over the course of nine years. The study found that those individuals that consumed artificially sweetened drinks, such as diet soda, displayed a 34 percent higher risk of developing metabolic syndrome, which carries with it an increased risk of heart disease.
The American Academy of Neurology studied the relationship of depression to diet sodas and other artificially sweeteners. Results showed that out of 263,925 adults, those who drank soda were 30 percent more likely to suffer from depression over a 10-year period.
Various groups have studied the correlation between diet sodas and other artificially sweetened drinks and Type 2 diabetes. According to the American Diabetes Association, out of a test group of 6,814 individuals, 67 percent of those that consumed diet sodas daily contracted Type 2 diabetes.