It may be due to the hormone 'ghrelin' secreted by the stomach that appetite runaway

by Viewminder

It has long been known that hormones called " ghrelin " made in the stomach on an empty stomach promote appetite. New studies have shown that ghrelin has the power to enhance appetite and has the power to make food "smell" attractive enough for that person.

Ghrelin Enhances Food Odor Conditioning in Healthy Humans: An fMRI Study: Cell Reports
https://www.cell.com/cell-reports/fulltext/S2211-1247(18)31772-8

Gut hormone increasing response to food | Newsroom - McGill University
https://www.mcgill.ca/newsroom/channels/news/gut-hormone-increases-response-food-292422

'Hunger Hormone' Ghrelin Aids Overindulgence - Scientific American https://www.scientificamerican.com/podcast/episode/hunger-hormone-ghrelin-aids-overindulgence/

Ghrelin is secreted in the stomach when the mealtime approaches, or when you are not eating anything for a long time, letting people inform you that "do not forget to eat". Previous studies have shown that rats injected with ghrelin tend to eat too much and that ghrelin has a negative effect on mouse decision making and impulse suppression .

Researchers at McGill University have already shown in the research that "people injected with ghrelin release dopamine, which tends to be overeating." The research team newly conducted experiments to search ghrelin's mechanism for 38 volunteers.

Experimental subjects first received training to associate "random photos" with "smells", such as "smell of wood and fresh baked bread". At this time one of the subjects was injected with ghrelin and the other was injected with saline.

by herryway

After that, the researcher scans the subject's brain with fMRI and checked which part is changing. As a result, it was said that the brains of subjects injected with ghrelin were activated only when seeing the picture associated with the smell of food. It seems that this part did not respond to the picture associated with the smell other than food. Also, as we asked subjects to evaluate the pictures, people injected with ghrelin had a tendency to highly appreciate the photos associated with the smell of food.

The results of this study indicate that ghrelin controls the degree to which the brain 's reward system relates' smell of food', and it is believed that ghrelin may be the key to changing the response to food. It is also suggested that hypersensitivity to gene-based "photos and smells related to food" exists because the site reacted in this experiment is related to the genotypic phenotype called endophenotype I will.

by rawpixel.com