A new study has found that eating highly processed carbohydrates can cause excess hunger, as well as stimulate the regions of the brain involved in reward and cravings.
The study of high-glycemic index foods by researchers at Boston Children’s Hospital investigated how eating is regulated by the dopamine-containing pleasure centers of the brain.
“Beyond reward and craving, this part of the brain is also linked to substance abuse and dependence, which raises the question as to whether certain foods might be addictive,” said David Ludwig, MD, PhD, and director of the New Balance Foundation Obesity Prevention Center.
To examine the link, researchers measured blood glucose levels and hunger. They also used functional magnetic resonance imaging (MRI) to observe brain activity in the four hours after a meal, a time period, they say, that influences eating behavior at the next meal.
The researchers recruited 12 overweight or obese men for the study. They had them eat two test meals made up of milkshakes that had the same calories, taste and sweetness.
While the two milkshakes were essentially the same, one contained rapidly digesting — or high-glycemic index — carbohydrates, while the other was made up of slowly digesting (or low-glycemic index) carbohydrates.
The researchers found that after the men drank the high-glycemic index milkshake, they experienced an initial surge in blood sugar levels, followed by sharp crash four hours later.
This decrease in blood glucose was associated with excessive hunger and intense activation of the nucleus accumbens, a critical brain region involved in addictive behaviors, according to the researchers.
“These findings suggest that limiting high-glycemic index carbohydrates like white bread and potatoes could help obese individuals reduce cravings and control the urge to overeat,” said Ludwig.
He acknowledges that the concept of food addiction remains provocative, noting that the findings from the new study suggest that more interventional and observational studies be done.
The study was published in the American Journal of Clinical Nutrition.
Source: Boston Children’s Hospital