Patients who lost more weight after gastric bypass surgery had greater activity in executive control regions of their brains when attempting to resist food cravings than those who shed fewer pounds, researchers reported here.

In a functional MRI study, more successful bariatric surgery patients had significantly greater activation of the dorsolateral prefrontal cortex when they were told to fight food cravings while looking at food pictures than those who were less successful, Rachel Goldman, PhD, of Bellevue Hospital at New York University in New York City, reported online in Obesity and at Obesity Week.

This region of the brain is associated with self-control in food-related decision making, and its stimulation can inhibit food craving, Goldman said.

"The difference between patients who are more successful is their ability to utilize executive control circuitry when told to resist food cravings," she reported during an oral presentation.

Although the overall success rates of the various bariatric surgery procedures are high, about 20% of patients don't lose the expected amount of weight or they eventually regain it.

The reasons for these effects are unclear, and little is known about how the brain influences obesity or how it changes after surgery. Obese patients may have heightened arousal to food cues, and previous work has shown that there are differences in neuronal responses to these food cues between overweight and normal-weight patients.

Continue reading...