Controlling food intake isn’t always a conscious decision, study suggests

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A new study found that visual food cues impact both conscious and unconscious behavior, indicating that dietary guidance alone may not be enough for patients with obesity to lose weight.

According to the study, efforts to control obesity usually involve regulating a patient’s eating behaviors with dietary guidance. However, research suggests that about half those who lose weight due to dietary guidance return to their original weight within five years. Published in the journal, PLOS ONE, this investigation sought to explain the limited effectiveness of dietary guidance and better understand the unconscious neural processes that impact eating behaviors.

To do this, a team of scientists led by Takahiro Yoshikawa, MD, a professor at the Graduate School of Medicine at Osaka Metropolitan University in Osaka, Japan, studied neural activity in response to unconscious and conscious visual food stimuli. In addition, participants answered a questionnaire on eating behaviors such as emotional eating and cognitive restraint of food intake.

The study’s results revealed that activity in the inferior frontal gyrus, a region of the brain’s frontal lobe that controls eating behavior, changed when visual food stimuli were presented consciously and unconsciously. In addition, researchers found that these changes correlated to the participants’ questionnaire answers.

According to researchers, these results indicate that both unconscious and conscious neural processes much be considered when studying ways to regulate eating behavior.

"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," said Yoshikawa.