Visual food cues can affect eating behavior - study

Controlling your food intake can be even more difficult than you think. Osaka Metropolitan University scientists show that visual food cues can affect your eating behavior even when you are not aware of them.

Obesity is one of the major pathological conditions that constitute lifestyle-related diseases and is known to be associated with myocardial infarction, stroke and cancers. Approaches to regulating eating behavior are widely used in an effort to control obesity, but about half of those who receive dietary guidance return to their original weight within five years.

To explain the limited effectiveness of such guidance, one hypothesis suggests that not only conscious neural processes, which the dietary guidance targets, but also unconscious neural processes play an important role in controlling eating behavior. However, there were no studies directly examining the validity of this hypothesis at the level of neural activity.

Thirty-one healthy male volunteers aged 19 to 25 participated in the study.

How did the scientists arrive at their conclusions?

The research team led by Prof. Takahiro Yoshikawa from the university’s Graduate School of Medicine has revealed that in the inferior frontal gyrus – a region of the brain’s frontal lobe that controls eating behavior – neural activity differs in response to visual food stimuli or food images, depending on whether those images are presented consciously or unconsciously. Using a questionnaire to assess the study participants, the team found that this difference was associated with their scores on eating behaviors, including emotional eating and cognitive restraint of food intake. These results indicate that eating behavior cannot be understood without taking into account both unconscious and conscious neural processes.

Their findings were published in PLOS ONE under the title “Association between eating behavior and the immediate neural activity caused by viewing food images presented in and out of awareness: A magnetoencephalography study.”

Osaka Metropolitan University is a new public institution of higher learning established last April, formed by a merger between Osaka City University and Osaka Prefecture University. 

“If we can learn more in future research about how eating behavior is controlled by unconscious neural processes, we can combine that understanding with our current knowledge of conscious neural processes to potentially develop more effective methods for regulating eating behavior,” Yoshikawa stated.