Processed carbohydrates tempt people to overeat
Washington: A new study has found that eating highly- processed carbohydrates like cakes, cookies and chips could affect pleasure centers in the brain, leading to serious cravings that might cause people to overeat.
Our brains consist of a complex network of pathways and regions that control for all our bodily functions. Chemical messengers called neurotransmitters allow signals to pass from one nerve cell to the next to aid in these functions.
One neurotransmitter, dopamine, plays a major role in the brain`s reward pathways.
For example, the brain gets flooded with dopamine when people take addictive drugs including cocaine and nicotine.
To find out how food intake was regulated by the dopamine -reward pathway, Ludwig and his colleagues recruited 12 overweight or obese men between the ages of 18 and 35 years old, CBS News reported.
On two occasions, they were fed milkshakes that were almost identical except one had a high-glycemic index and one was low-glycemic.
High-glycemic carbohydrates get digested rapidly, and include white bread, pasta, rice and baked goods, WebMD notes. Low-glycemic carbs are digested much slower, and include fruits, vegetables, unprocessed whole grains and legumes.
Four hours after the meals, they were given fMRI brain scans that measured activity of these networks and pathways.
Participants who drank the high-glycemic milkshakes saw their blood sugar levels surge, only to sharply crash four hours later.
When their blood sugar dropped, not only did they feel excessive hunger, but the fMRIs showed "intense" activation in the nucleus accumbens, a region of the brain involved in addiction.
This study showed that when calories and sweetness are equal, glycemic index could still trigger brain changes that might lead to overeating.
"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," Ludwig said.
The research is published in the American Journal of Clinical Nutrition.