Glucose and fructose are both sugar molecules used by the human body to power many of its cellular processes. However, research has linked the fructose added to processed foods – in the form of high-fructose corn syrup – to obesity and overeating.

Now, a team of nutrition and mental health experts has found what they believe is an explanation for this form of fructose’s effect on eating habits.

Using magnetic resonance imaging, researchers from Oregon Health and Science University measured the brain activity of nine healthy adults. Each adult was given an injected solution of either fructose, glucose or water.

Those given glucose reportedly showed less neural activity in their cerebral cortices, which are areas of the brain responsible for the senses of taste and smell, as well as for exercising restraint.

On the other hand, participants injected with fructose showed greater than average cortical activity. The team theorized that fructose, particularly that found in high-fructose corn syrup, may negatively affect the neurological ability of eaters to avoid processed foods.

Sweetened foods have contributed to the growing problem of obesity in the U.S., which many health authorities have labeled an “epidemic.”

Currently, two-thirds of Americans are either overweight or obese, according to the Centers for Disease Control and Prevention.