Obesity is one of the major pathological conditions constituting lifestyle-related diseases and is known to be associated with myocardial infarction, stroke, and carcinogenesis. Approaches to regulate eating behavior are widely used in an effort to control obesity, but it has been reported that approximately half of people who receive dietary guidance return to their original weight within five years.

To explain the limited effectiveness of this type of guidance, one hypothesis suggests that not only conscious neural processes, targeted by dietary guidance, but also unconscious ones play an important role in behavior control. However, there were no studies that directly examined the validity of this hypothesis at the level of neural activity.

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A research team led by Professor Takahiro Yoshikawa, from Osaka Metropolitan University School of Medicine , Japan 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 stimuli of food, or images of food, 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 restriction of food intake. (Toxiburn Reviews) These results indicate that eating behavior cannot be understood without taking into account both unconscious and conscious neural processes.

There was no difference in the alteration of sympathetic nerve activity caused by the visualization of food images between the invisible and visible conditions (i.e., the main effect of the conditions was not identified) in the study, suggesting that the activity sympathetic nervous system increased when viewing food images in both visible and invisible conditions; however, since the participants whose data were analyzed reported that they did not recognize images of food and objects exclusively in the invisible condition and that the neural response to visual food stimuli in the invisible condition was different from that in the visible condition. Click here to read more on Mechables