Nutrition experts have taught us some fats are worse for you than others. Now new research suggests the same may be true for different types of sugars.

Overweight adults who consume a large amount of fructose have been shown to experience wild fluctuations in body fat and insulin sensitivity. The same results were not found among those who consumed similar amounts of glucose.

The results may seem surprising because pure fructose is found in fresh fruit, fruit juice and preserves. But fructose also sneaks into our diets via high-fructose corn syrup, which is found in soft drinks and other processed foods. It is also found in sucrose, or ordinary sugar, which the body breaks down into fifty-five percent fructose and forty-five percent glucose.

Glucose, on the other hand, is produced when the body digests carbohydrates.

In a recent study led by researchers at the University of California, Davis, a group of overweight or obese adults were asked to consume a diet in which twenty-five percent of their energy came from either fructose or glucose.

Among adults who consumed fructose, the scientists found an increase in the amount of intra-abdominal fat, which creates a potbelly and has been linked to an increased risk of heart disease and diabetes. The fructose group also had elevated levels of fatty triglycerides, while their insulin sensitivity plunged by twenty percent.

What’s a discerning diner to do? Some would say the study merely re-enforces common sense… beware the sour side of sweets, and consider healthier alternatives.