Then, with regards to association with heart disease, it doesn't matter which one you chose, both are linked to increased risk of heart disease and developing metabolic syndrome.

Metabolic syndrome is a cluster of cardiovascular disease and diabetes risk factors including excess waist circumference, high blood pressure, elevated triglycerides, low levels of high-density lipoprotein (HDL "good" cholesterol) and high fasting glucose levels -- three or more of which, increases a person's risk of developing diabetes and cardiovascular disease. It also increases the risk of heart disease by two to four times that than the normal population and increases the risk of type-2 diabetes by nine to 30 times, not to mention its detrimental effects to the kidneys, liver, ovaries, a person's ability to sleep and even dementia.

According to statistics, metabolic syndrome affects up to 30 percent of the industrialized world's population, and is expected to affect 50 to 75 million Americans by the year 2010.

As reported by the Framingham researchers in Circulation: Journal of the American Heart Association, drinking one or more soft drink daily (whether regular or diet) may increase the risk factors for heart disease, among others:
- 31 percent greater risk of developing new-onset obesity (defined as a body mass index [BMI] of 30 kilograms/meter2 or more);
- 30 percent increased risk of developing increased waist circumference;
- 25 percent increased risk of developing high blood triglycerides or high fasting blood glucose;
- 32 percent higher risk of having low HDL levels.

A trend towards an increased risk of developing high blood pressure that was not statistically significant. According to Ravi Dhingra, M.D., lead author of the study and an instructor in medicine at Harvard Medical School: "Moderation in anything is the key. If you are drinking one or more soft drinks a day, you may be increasing your risk of developing metabolic risk factors for heart disease."

For those who already have diabetes, soft drinks are double trouble anyway. What with all that sugar content!

Also, According to Ramachandran Vasan, M.D., senior author of the Framingham Heart Study and professor of medicine at Boston University School of Medicine: One explanation is that the fructose corn syrup in regular soft drinks causes weight gain, and can lead to insulin resistance and diabetes. But then you would expect to see an association with regular soft drinks, but not diet soft drinks.

Our findings suggest that this is not the case. Another possible explanation is that consuming more liquids is associated with a lesser degree of dietary compensation. However, the researchers admit that these results need to be replicated in further studies before recommendations can be made.