"This is your brain on sugar – for real. Scientists have used imaging tests to show for the first time that fructose, a sugar that saturates the American diet, can trigger brain changes that may lead to overeating."
Suspicions about high fructose foods have been evident for the last decade, but now more acute study has shown this sugar's serious negative health side effects.
For the study, scientists used magnetic resonance imaging, or MRI, scans to track blood flow in the brain in 20 young, normal-weight people before and after they had drinks containing glucose or fructose in two sessions several weeks apart.
Scans showed that drinking glucose "turns off or suppresses the activity of areas of the brain that are critical for reward and desire for food," said one study leader, Yale University endocrinologist Dr. Robert Sherwin. With fructose, "we don't see those changes," he said. "As a result, the desire to eat continues – it isn't turned off."
What's convincing, said Dr. Jonathan Purnell, an endocrinologist at Oregon Health & Science University, is that the imaging results mirrored how hungry the people said they felt, as well as what earlier studies found in animals.
"It implies that fructose, at least with regards to promoting food intake and weight gain, is a bad actor compared to glucose," said Purnell. He wrote a commentary that appears with the federally funded study in Wednesday's Journal of the American Medical Association.
Researchers now are testing obese people to see if they react the same way to fructose and glucose as the normal-weight people in this study did.