Some weight-loss surgeries can diminish cravings for sweets by altering the brain's response to the neurotransmitter dopamine.

Ivan de Araujo of Yale University in New Haven, Connecticut, and his colleagues studied the effects of a duodenal–jejunal bypass, which reroutes food from the stomach directly into the middle part of the small intestine. They found that well-fed mice that did not have the surgery consumed more sugar after previous repeated exposure to sweets. Mice that had the surgery did not develop the same sweet tooth.

Sugar consumption led to the release of dopamine, which is involved in reward responses, particularly when the sugar was administered to the upper region of the intestines (the area bypassed in the surgery). Activating dopamine-sensing neurons restored the sweet cravings in mice that had undergone the surgery.

Cell Metab. http://doi.org/9dm (2015)