High fructose, higher cravings

Dr. Ludwig and his colleagues recruited a dozen obese men and fed them milkshakes on two different occasions separated by several weeks. On one occasion, the shakes were made with high-glycemic corn syrup; on the other, a source of low-glycemic carbohydrates was used.

What they found was that four hours after drinking the high-glycemic shake, blood sugar levels had plummeted into the hypoglycemic range, the subjects reported more hunger, and brain scans showed greater activation in parts of the brain that regulate cravings, reward and addictive behaviors. 

NYT: How Carbs Can Trigger Food Cravings