A recent paper by Dr Suzanne Higgs & Dr Jason Thomas published in the American Journal of Clinical Nutrition (Impact Factor = 6.9) reports the results of a study on the brain processes involved in control of meal size. Participants in the study were scanned using functional magnetic resonance imaging (fMRI) on two separate test days, before and after eating a meal. During scanning, they tasted chocolate and strawberry flavours and saw pictures of these foods whilst their brain responses were recorded. After eating the meal (compared to no meal), brain responses to the chocolate and strawberry stimuli were greatly reduced in areas of the brain associated with the pleasures of eating. In other words, food became less attractive after eating, which is not a surprise. However, what was more surprising was that brain responses to the chocolate and strawberry were increased in an area important for higher cognitive processes, such as memory, response inhibition and attention (dorsolateral prefrontal cortex).
According to Dr Thomas “This work is fascinating as it shows that brain responses in both reward and cognitive control areas are affected by the consumption of a meal and hints that processes such as memory, attention and response inhibition are important in determining when we stop eating”.
The paper ‘Satiation attenuates BOLD activity in brain regions involved in reward and increases activity in dorsolateral prefrontal cortex: an fMRI study in healthy volunteers can be read here , and was co-authored by: Dr Colin Dourish from P1vital (a clinical research organisation specialising in experimental medicine); Dr Peter Hansen from University of Birmingham; Prof Catherine Harmer from University of Oxford; and Dr Ciara McCabe from University of Reading.