This article is more than 5 years old. Information may no longer be current.
Reward-based learning impaired for women with obesity when it comes to food
Click Here to Manage Email Alerts
A deficit discovered in reward-based learning, specific to food, among women with obesity highlights the behavioral aspects of the epidemic and holds potential for combating it, according to a report published in Current Biology.
“Women with obesity were impaired at learning which cues predict food and which do not, but had no trouble learning similar associations with money,” Ifat Levy, PhD, of the Yale School of Medicine, told Endocrine Today.
The impairment was markedly different in women with obesity vs. those with normal weight, and not seen in men, in an appetitive reversal paradigm conducted by Zhihao Zhang, a PhD candidate at Yale University, and colleagues, including Levy.
“Although we do not know whether this impairment is a cause for obesity or its effect, this finding provides a link between reward learning and obesity, which can now be used to further probe these questions,” Levy said.
Ifat Levy
The researchers recruited participants based on BMI, then crossed body weight status (normal weight or obese), reward modality (food or money) and sex (male or female) to create eight distinct groups. No significant differences in BMI existed in the normal-weight or obese groups, nor in age, income, education and self-reported hunger level.
Participants completed tasks with an acquisition stage, followed by transition to a reversal stage without signal. Blue and purple squares were used as conditioned stimuli; reward followed one color during acquisition, then switched colors during reversal — both in only one-third of trials.
Researchers asked participants to share their reward expectancy, on a scale of 1 to 9. Domain specificity was tested in a between-subject design, using pictures of food (peanut M&Ms or pretzels) and money.
Compared with men in the obese group and participants with normal weight, women in the obese group struggled to make accurate predictions when the reward was pretzels or chocolate candies, but not money.
Zhihao Zhang
“Since women with obesity may have a problem in learning about cues in the environment that predict food, such that they create incorrect associations between cues and food, an exciting idea is that perhaps by modifying these flawed associations in a behavioral intervention we can also modify eating behavior,” Levy said.
Such interventions would shift the attention away from how people with obesity react to food and toward how they learn about their environment and navigate cues, Zhang told Endocrine Today.
“Rather than target individuals’ behavior with food, we suggest that a successful intervention should aim to modify their interactions with other cues that determine their eating patterns,” Zhang said. “Also, the difference we found between obese males and females stresses the importance of sex-appropriate interventions.”
The investigators have an immediate plan to use MRI to examine the neural basis of the differences, Levy said, recognizing the prefrontal cortex is involved in this type of learning.
Two other areas invite further exploration to determine whether impaired food learning is a cause for obesity, its effect, or both, Levy added.
“We would also love to examine behavioral and neural function in individuals with obesity before and after a weight-loss intervention or bariatric surgery, as well as in children who are at risk for obesity, but are not obese yet,” Levy said. — by Allegra Tiver
For more information:
Levy can be reached at 310 Cedar St., Room BML 330A or P.O Box 208016, New Haven, CT 06520; email: ifat.levy@yale.edu.
Zhang can be reached zhihao.zhang@yale.edu.
Disclosure: The researchers report no relevant financial disclosures.
Click Here to Manage Email Alerts