Obese Children Demonstrate Different Response to Food Odors

(HealthDay News) — Obese children may have difficulty resisting food because of how their brain is wired, a new study suggests. 

The findings were scheduled to be presented at the annual meeting of the Radiological Society of North America in Chicago.

The researchers used 2 types of magnetic resonance imaging (MRI) to compare brain imaging results from 30 children aged 6 to 10 years. During the MRI, the children smelled chocolate, onion, and a non-food smell of diluted acetone, the active ingredient in nail polish remover. Half the children had a BMI between 19 and 24, and half had a BMI greater than 30.

When the children with obesity smelled the chocolate or onion, the researchers saw activity in the part of their brain involved in impulsive decisions but did not see activity in the part of the brain that controls the impulse to eat, study author Pilar Dies-Suarez, MD, head of radiology at the Federico Gomez Children’s Hospital of Mexico in Mexico City, told HealthDay. When the children with normal BMI smelled food, the researchers saw activity in parts of the brain related to regulating pleasure, planning, and emotional processing or memory. 

The brain responses in children with obesity were also much greater when they smelled the chocolate and the onion compared with the responses in the normal-weight children. When the obese children smelled the acetone, the active parts of their brain were related to memories and risk assessment.

“This probably shows the brain processing of a smell which is not that usual,” possibly trying to determine whether it’s a safe food, Dr Dies-Suarez said. “In contrast, the normal-weight volunteers seemed to be uninterested in this stimulus.”


  1. Dies-Suarez P, Hidalgo-Tobon S, De Celis IV B, Barragan E, Ibanez P, Obregon M. Obese children fMRI brain connections for food odor stimuli. Presented at the Radiological Society of North America Annual Meeting; November 29-December 4, 2015; Chicago, IL.
  2. Food Odors Activate Impulse Area of the Brain in Obese Children [press release]. Radiological Society of North America; November 24, 2015. https://www2.rsna.org/timssnet/media/pressreleases/14_pr_target.cfm?ID=1837. Accessed November 25, 2015.