People joke they're addicted to desserts, but new brain imaging research shows there may be some truth to the statement.

Researchers have found 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.

"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 study author Dr. David Ludwig, director of the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital.

One human neurotransmitter, dopamine, plays a major role in the brain's reward pathways. Dopamine floods the brain from addictive drugs including cocaine and nicotine. What about food intake?

Ludwig and his colleagues fed 12 overweight or obese men between the ages of 18 and 35 years old milkshakes that were almost identical except one had a high-glycemic index and one was low-glycemic.

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 brain scans showed "intense" activation in the nucleus accumbens, a region of the brain involved in addiction.

The researchers pointed out previous studies comparing eating vegetables or high-calorie cheesecakes also showed different brain reactions. But, this study showed that when calories and sweetness are equal, glycemic index could still trigger brain changes that might lead to overeating.

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