Study: Women less able to suppress hunger

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Study: Women less able to suppress hunger

By RANDOLPH E. SCHMID (AP Science Writer)

From Associated Press

January 19, 2009 6:08 PM EST

WASHINGTON - Faced with their favorite foods, women are less able than men to

suppress their hunger, a discovery that may help explain the higher obesity rate

for females, a new study suggests.

U. S. researchers trying to understand the brain's mechanisms for controlling

food intake were surprised at the difference between the sexes in brain

response.

Gene-Jack Wang of Brookhaven National Laboratory and colleagues were trying to

figure out why some people overeat and gain weight while others don't.

They performed brain scans on 13 women and 10 men, who had fasted overnight, to

determine how their brains responded to the sight of their favorite foods. They

report their findings in Tuesday's edition of Proceedings of the National

Academy of Sciences.

" There is something going on in the female, " Wang said in a telephone interview,

" the signal is so much different. "

In the study, participants were quizzed about their favorite foods, which ranged

from pizza to cinnamon buns and burgers to chocolate cake, and then were asked

to fast overnight.

The next day they underwent brain scans while being presented with their

favorite foods. In addition, they used a technique called cognitive inhibition,

which they had been taught, to suppress thoughts of hunger and eating.

While both men and women said the inhibition technique decreased their hunger,

the brain scans showed that men's brain activity actually decreased, while the

part of women's brains that responds to food remained active.

" Even though the women said they were less hungry when trying to inhibit their

response to the food, their brains were still firing away in the regions that

control the drive to eat, " Wang said.

Nora Volkow, director of the National Institute on Drug Addiction and a

co-author of the paper, said the gender difference was a surprise and may be

because of different nutritional needs for men and women, although she stressed

that idea is speculative.

Because the traditional role of the female is to provide nutrition to children,

the female brain may be hard-wired to eat when foods are available, she said.

The next step is to see if female hormones are reacting directly with those

specific parts of the brain.

" In our society we are being constantly being bombarded by food stimulus, " she

said in a telephone interview, so understanding the brain's response can help in

developing ways to resist that stimulus.

Stice, an expert on eating disorders at the Oregon Research Institute,

called the findings provocative.

" I think it is very possible that the differences in hunger suppression may

contribute to gender differences in eating disorders and that they are likely

linked to gender differences in estrogen and related hormones, " said Stice, who

was not part of Wang's research team.

According to the Centers for Disease Control and Prevention, 35.3 percent of

American women and 33.3 percent of men were considered obese in 2006.

lyn Weller, a professor of psychology at the University of

Alabama-Birmingham, said she was surprised by the results and " thought the

dissociation between subjective reports of hunger and brain activation in women

but not men was very interesting. "

The results suggest that training in reducing food desires or in reacting to

food cues could be effective treatments to combat obesity, said Weller, who was

not part of the research team.

Weller was a co-author of a recent paper in the journal NeuroImage that studied

women's brains when participants were shown pictures of food. They found that

obese women had a much stronger reaction than normal-weight women in brain

regions related to reward.

Wang noted that behavioral studies have shown that women have a higher tendency

than men to overeat when presented with tasty food or under emotional distress.

This may result from differences in sex hormones, he said, and further research

is planned to see if that is the case.

Alice H. Lichtenstein, an expert in eating behavior at Tufts University, called

Wang's research " very interesting ... I hope to see more like it. "

But, she added, a lot of different factors figure in what and when we eat.

" As we learn more about the different factors that go into making that decision

we'll be better at helping people regulate " their eating, said Lichtenstein, who

was not part of the research team.

Obesity has been increasing and Wang also suggested that another part of the

reason is changes in society.

While food choices were seasonal and more limited for our ancestors, choices

today are wider and the food is so tempting, he said.

" You go to the buffet, you see the food, you want it, " Wang went on. " Some

people go to the buffet, they don't eat so much, some do. There is something

different in the people. "

The study was funded by the National Institute on Drug Abuse, the National

Institute on Alcohol Abuse and Alcoholism, and by the General Clinical Research

Center of Stony Brook University.

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