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Is overeating a conditioned response?


For decades, researchers have been trying to understand the mechanisms behind eating disorders.

One of the most pressing and perhaps unanswerable questions has been, "Why do people eat even when they're not hungry?"

A new study from the University of California's San Diego School of Medicine suggests that overeating may be a conditioned response.

The Pavlov effect

Similar to the story of Pavlov's dogs - who become conditioned to salivate in response to certain cues - people can also be conditioned to salivate, and therefore overeat, the researchers found.

The study enlisted 16 overweight and 17 lean participants who were shown visual cues and corresponding "rewards": after they were shown a circle, they got a sip of water; after they were shown a square, they got a sip of chocolate milk; and after they were shown a triangle, they received nothing.

Researchers attached electrodes to the back of the participants' necks to measure the rate of swallowing, which is an indicator of salivation.

Overweight participants salivated more

Interestingly, overweight participants were shown to swallow three times as often as the lean subjects when they were shown the square (which was associated with the chocolate milk reward).

According to the researchers, obese individuals may be more susceptible to food cues and have a stronger reactive nature when it comes to these cues.

“We think that people who are overweight are more likely to form conditioned responses to food, which can easily lead to overeating,” said study author Kerri Boutelle, PhD, professor of pediatrics and psychiatry. “Our study is the first to show a difference in the acquisition of Pavlovian learning in overweight and lean individuals.”

The study is published in Contemporary Clinical Trials.

Source: ZME Science