Previous studies have found obesity can affect parts of the brain involved with memory and learning but researchers say this is the first study to show it may have an effect on the function of memory. Photo by Suzanne Tucker/Shutterstock

CAMBRIDGE, England, Feb. 26 (UPI) -- Changes to the brain caused by obesity may harm memory, which researchers in a recent study think could influence people to eat more and gain more weight.

The association between weight and dysfunction in areas of the brain is not a new one, and now a small study in England has found participants with higher body mass indexes showed worse episodic memory when tested.


While the researchers say they're not necessarily making a case that overweight people are more forgetful, the suggestion that incomplete or unformed memories of previous meals may influence overeating.

The theory, they said, is based on previous studies showing obesity has a negative effect on the hippocampus, involved in memory and learning, and frontal lobe, which is involved in decision making, problem solving, and emotions. There is not much previous evidence that obesity can affect memory, though.

"It is possible that becoming overweight may make it harder to keep track of what and how much you have eaten, potentially making you more likely to overeat," Dr. Lucy Cheke, a researcher at the University of Cambridge, said in a press release. "The possibility that there may be episodic memory deficits in overweight individuals is of concern, especially given the growing evidence that episodic memory may have a considerable influence on feeding behavior and appetite regulation."

For the study, published in the Quarterly Journal of Experimental Psychology, researchers recruited 50 participants between the ages of 18 and 35 with BMI between 18 and 51 for a what-where-when test of episodic memory. Among the participants, 26 had a BMI less than 25 and were considered lean, while 24 had a BMI above 25 and were considered either overweight or obese. A BMI of 30 is considered obese.

The study participants were asked to complete a computerized treasure hunt by hiding items, and then in memory tests over the following two days were asked to remember which items they hid, where, and when.

Overall, the researchers found participants with higher BMI performed more poorly on the tasks, but did not perform worse as the difficulty of tasks increased. When considered separately, age, years in education and gender didn't predict differences in performance, however they may play a small role when considered with BMI, the researchers reported.

"Increasingly, we're beginning to see that memory -- especially episodic memory, the kind where you mentally relive a past event -- is also important," Cheke said. "How vividly we remember a recent meal, for example today's lunch, can make a difference to how hungry we feel and how much we are likely to reach out for that tasty chocolate bar later on."