Obesity, Gender, and The Quirky Human Brain

At the Brookhaven National Laboratory scientists are learning why women have more difficulty controlling their appetite. Turns out that men seem to be able to actually change how their brains respond to tasty foods, while women generally lack the ability.
From Brookhaven NL:

The scientists used positron emission tomography (PET) scanning to monitor brain activity in 13 female and 10 male volunteers. In this method, a form of glucose “tagged” with a radioactive tracer molecule is injected into the blood stream while subjects lie in the PET scanner. The scanner tracks the tracer’s signal to monitor the uptake and use of the glucose by various regions of the brain. All study subjects were of normal body weight and had fasted for nearly 20 hours before each of three separate scans, performed in random order.
On one scan day, subjects were presented with their favorite foods — from bacon-egg-and-cheese sandwiches to pizza, cinnamon buns, barbecue ribs, and chocolate cake — warmed, if appropriate, to enhance the enticing aromas and taste. During the scan, subjects were asked to smell, taste, observe, and react to the food, but not eat it. On another day, they were instructed to inhibit their desire for food prior to being tempted with the same foods. A control scan with no food was performed on another day.
The volunteers were also asked to rate the foods and describe their feelings of hunger and their desire to eat during the scans when food was presented.
In both men and women, a variety of brain areas associated with emotional regulation, conditioning, and motivation “lit up,” indicating increased metabolic activity in those regions, in response to the tempting foods when compared with the no-food scans — a finding consistent with earlier work using the same setup at Brookhaven Lab. When asked to inhibit their response to food, both men and women described themselves as less hungry and less interested in eating than when they weren’t trying to inhibit their response. But only the men showed a relative decrease in activity in the food-activated brain regions during the scan when they were asked to inhibit their response.

Press release: Control Your Hunger? Study Shows Men Can, Women Can’t
Image: Each brain image shows the change in brain metabolism when subjects were asked to inhibit their response to food during food stimulation compared with when they were not told to inhibit their response. Two brain sections at different levels of the brain are shown for each group (women, men, and women vs. men). Top row, women: No color indicates that women had no significant differences in brain activity between the two conditions. Middle row, men: Blue colored areas were significantly less active when men were told to inhibit their response to food than they were without inhibition. Third row, women vs. men: Orange color indicates areas where men showed greater decrements with inhibition than women. These brain regions are involved in emotional regulation, conditioning, and the motivation to eat.