After having a drink that contained glucose, the activity of areas of the brain that control reward and appetite are turned off, the study showed. Researchers studied magnetic resonance imaging scans of 20 participants before and after drinking glucose or fructose in two sessions several weeks apart. Drinking fructose did not seem to have the same impact on appetite, meaning that people wanted to continue eating, study leader endocrinologist Dr Robert Sherwin said.
Fructose and high-fructose corn syrup are often added to processed foods and beverages. The findings show that these sugars may play a role in causing obesity because they can trigger changes in the brain that may result in overeating.
Dr Jonathan Purnell, an endocrinologist at Oregon Health and Science University, who wrote a commentary accompanying the study, said that the imaging results mirrored what people said when asked how hungry they felt. They also confirmed the findings of previous studies on animals.
According to Purnell, the study suggested that fructose was a bad factor when it came to promotion of food intake and weight gain. People should avoid processed foods that contain fructose and high-fructose corn syrup and limit the sugar-sweetened beverages, he added.
Researchers are now studying the impact of fructose and glucose on obese people to compare their reaction with that of normal-weight people in this study.