Food Cues We’re Not Aware of Can Influence Our Eating Behavior

Dieting can be difficult, with many different approaches available for regulating eating behavior. New research from Osaka Metropolitan University has illustrated that it’s not just conscious neural processes that impact our eating behavior, but unconscious processes as well. The study is published in PLOS One.

Long-term weight loss isn’t always successful

Obesity has been linked to an increased risk of developing type 2 diabetes, high blood pressure, cancer, stroke and many other health conditions. Rates of obesity are on the rise, nearly tripling between 1975 and 2016.

A meta-analysis of 29 long-term weight loss studies revealed that more than 80% of the weight lost while dieting is regained within 5 years. The current study aimed to explain why receiving dietary guidance isn’t always a successful approach to long-term weight loss.

Traditional dietary guidance targets conscious decision-making processes, so the team, led by Professor Takahiro Yoshikawa, aimed to examine the impact of unconscious neural processes on appetite regulation.

Food cues we’re unaware of have an impact too

Study participants were shown pictures of food above and below the threshold of awareness, using a visual backwards masking procedure, and their brain activity was monitored using magnetoencephalography, which measures the electrical activity of neurons.

The researchers revealed that in a region of the brain that controls eating behavior – the inferior frontal gyrus – neural activity differed in response to consciously presented and unconsciously presented food images.

After being shown the food images, participants completed a questionnaire that the researchers used to associate the difference in brain activity with a difference in eating behaviors, including cognitive restraint on food intake and emotional eating.

The major takeaway from this research is that both conscious and unconscious neural processes contribute to our eating behavior, and as such, “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 Professor Yoshikawa.

Reference: Ishida R, Ishii A, Matsuo T, Minami T, Yoshikawa T. Association between eating behavior and the immediate neural activity caused by viewing food images presented in and out of awareness: A magnetoencephalography study. PLOS ONE. 2022;17(12):e0275959. doi: 10.1371/journal.pone.0275959

This article is a rework of a press release from Osaka Metropolitan University. Material has been edited for length and content.