Why do women seem to have a much harder time sticking to their diets than men do? A new study provides a provocative clue: Women’s brains appear to have more of a mind of their own, so to speak, when food beckons.

Gene-Jack Wang of the Brookhaven National Laboratory and his colleagues quizzed 13 healthy women and 10 men about their favorite foods and then asked them to fast for at least 17 hours before coming in for a series of brain scans.

Before two of the scans, the researchers tempted the subjects with their favorite foods, whether it was lasagna, pizza, cinnamon buns, barbecue ribs or chocolate cake. The subjects could smell and even taste the food, but they couldn’t eat it. Before one of the scans they were asked to try to suppress their impulse to indulge by trying to think about something else. They were also asked to describe how hungry they were and how strong their desire to eat was.

In both men and women, a variety of brain areas associated with regulating emotions, desire, conditioning, habit and motivation lit up when the subjects were tempted with their favorite foods. And both men and women described themselves as less hungry and less interested in eating when they tried to suppress their appetite.

But only the men showed a decrease in activity in the parts of the brain activated by food when they tried to tamp down their appetite, the researchers report in the Proceedings of the National Academy of Sciences.

The researchers are unsure why these sex differences exist, but it may be because of the difference in sex hormones such as estrogen.
— Rob Stein