Whether it is diet or regular, researchers say that one soda pop a day is too many.  According to Ramachandran Vasan, MD, professor of medicine at Boston University School of Medicine, drinking one serving of soda a day increases your risk of metabolic syndrome by 50% and may, in turn, lead to heart disease.

To be diagnosed with metabolic syndrome, three of five criteria must be met: a large waistline, elevated blood pressure, elevated fasting blood sugar, elevated fasting triglycerides, or reduced HDL or "good" cholesterol.

Lifestyle factors such as a high intake of calories from non-nutritious sources and a lack of exercise are the main culprits to metabolic syndrome, but this study pinpoints a particular disastrous activity (drinking soda) that proves to be a major contributor to elevating risk factors.

Is there a "safe" amount of soda? "We cannot really answer that question," Vasan says. The research shows an association between soda consumption and metabolic syndrome risk, Vasan says, but not cause-effect. More study is needed.

Soda pop also has a bad reputation of contributing to bone loss, elevating blood sugar levels and leading to fat gain and obesity, and increasing your risk of pancreatic cancer.