A Strange New Insight Into Female Obesity

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Obesity is complicated. It's commonly portrayed as a matter of self-control, but the underlying causes — psychological, physiological, and others — interact in unexpected ways, making this a very difficult condition to treat. And a new study in Current Biology offers an unexpected new layer: Obese women, but not men, apparently have a deficit when it comes to food-related learning tasks — that is, to responding accurately to certain cues.

The press release explains:

"Our study shows that obesity may involve a specific impairment not in the processing of food itself, but rather in how obese individuals—or at least obese women—learn about cues in the environment that predict food," says Ifat Levy of Yale University. "This is not a general learning impairment, as obese women had no problem [learning] when the reward was money rather than food. An intriguing possibility is that, by modifying flawed associations between food and environmental cues, we may be able to change eating patterns."

To test the ability of normal-weight and obese men and women of acquiring and modifying cue-reward associations, the researchers presented participants with one of two colored squares followed by a reward (a picture of either money or food) or not. In the first phase, the reward always followed one of the two colors. Later, the researchers reversed that predictable color association. Along the way, study participants were asked to predict the likelihood of a reward after seeing one color or another.

These studies showed that obese women struggled to make those predictions as accurately as normal-weight individuals or as obese men did when the reward was food, either pretzels or chocolate candies, as opposed to money. The gender difference came as a surprise to the researchers, who say they had expected to see a similar pattern in both obese men and women.

The researchers say they aren't sure of what accounts for this gender difference, but that it could have to do with the fact that women generally deal with different (and often more severe) body-image issues than men.

Whatever the reason for this strange finding, it could point toward improved treatments for obesity in the future. A lot of what we eat, after all, has more to do with cues, social and otherwise, than with carefully thinking through what we're putting into our bodies.