The type of sugar you eat may cause you to eat too much. Your brain can tell the difference between fructose and glucose, and the difference may influence whether you are slim or obese.

A study from the American College of Neuropsychopharmacology found that fructose, the type of sugar found in high-fructose corn syrup, doesn't produce satiety — the sensation of fullness — and instead triggers activity in the brain that encourages a person to eat more.

Fructose is the simple sugar found in fruits, but it is processed into a refined sugar in the form of high-fructose corn syrup. When ingested, it produces fewer satiety hormones than when glucose is eaten, and tests show it causes rodents to eat more.

Glucose is the body's main energy source. It is produced when complex carbohydrates break down naturally in the body. Glucose produces a feeling a satiety in the body, or the feeling of fullness.

Researchers at the Keck School of Medicine of the University of Southern California enlisted 24 volunteers, 16 to 25 years of age. The volunteers were asked how badly they wanted to eat based on a scale of 1 to 10. They then drank a beverage containing either glucose or fructose.

After drinking the beverage, the volunteers were given functional MRI scans of their brain. They were shown pictures of food and other objects, and asked again how badly they wanted to eat.

People who drank the fructose drink reported greater hunger than those who consumed the glucose drink. At the same time, the MRI showed greater activity in the reward centers of the brain when shown photos of high-fat foods. The heightened activity provoked an increased motivation to eat.

Researchers suggest that the high amounts of fructose in the form of high-fructose corn syrup that is added to hundreds of foods and beverages, affect the area of the brain that helps control appetite and the urge to eat.

The bottom line? People are more likely to remain hungry after a meal high in fructose than one high in glucose, and will be more likely to overeat while indulging in high-fat foods.