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The brain of obese people shows greater activation before food than money, according to a study

Spanish version: sl.ugr.es/comida_dinero

Scientists from the Mind, Brain and Behavior Research Center (CIMCYC) at the University of Granada have used functional magnetic resonance imaging (fMRI) to evaluate the behavior of the brain’s reward circuit (brain regions related to motivation, desire and pleasure, among others) in people with obesity, overweight and normal weight, while performing tasks related to food and money

The brain reward system of obese people shows greater activation to a food stimulus than an economic reward, according to scientists from the Mind, Brain and Behavior Research Center (CIMCYC, from its abbreviation in Spanish) at the University of Granada (UGR).

In a paper published in the journal Human Brain Mapping, researchers used the functional MRI to evaluate the behavior of the brain reward circuit (brain regions related to motivation, desire and pleasure, among others) in people with obesity, overweight and normal weight, while performing tasks related to food and money.

It is well known that when people with excess weight observe images of foods with high fat and sugar content, they present a greater activation of the brain reward circuit. However, until now, little was known about whether other more generic stimuli, such as money, could also have the same effect on this type of population.

To carry out this research, the authors worked with a sample of 21 adults with obesity, 21 overweight and 39 with a normal weight. They were presented with a series of images of food, some more appetizing than others (for example, hamburgers and fruit), and asked how much money they would be willing to pay for it.

They also had a test in which they had to press a button when they saw a star appear on the screen, and they were told that if they were right they would receive a reward of 2, 5 or 10 euros.

Sugars and fats

The results obtained during the research have replicated previous studies, and they show that a higher body mass index (BMI) is related to an increased activity of the brain reward circuit when watching images of food with high amounts of sugar or fat.

On the contrary, during the task where money could be obtained, overweight people, not obese ones, were the ones that presented a greater activation of the reward circuit. When a certain threshold is reached (BMI between 27 and 32), there is a decrease in the reactivity evoked by the expectation of obtaining money. Thus, individuals with obesity show neural patterns similar to those with normal weight.

“These results point to the need to expand the target of interventions beyond the brain’s reaction to food and include other stimuli. In addition, it would be wise to carry out specific interventions differentiating between people with obesity and overweight, since they show different brain patterns”, Raquel Vilar and Juan Verdejo, two of the authors of this paper, say.

In light of the results of this study, the objective of the interventions with overweight people, who show a high motivation for any type of stimulus, could be aimed at reducing this general reactivity, according to the researchers.

“However, with people with obesity who only show a greater brain reaction to food, a possible therapeutic approach may be to stimulate their brain reward system with other type of enhancers, in order to achieve a brain reaction similar to that caused by the visualization of food, so that the latter is not the dominant stimulus”, said Vilar and Verdejo.

Bibliographic references:

Brain reward system’s alterations in response to food and monetary stimuli in overweight and obese individuals

Verdejo-Román J, Vilar-López R, Navas JF, Soriano-Mas C, Verdejo-García A.Hum Brain Mapp. 2016 Sep 23.

DOI: 10.1002/hbm.23407

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  1. The authors of this research, Raquel Vilar and Juan Verdejo, from the Mind, Brain and Behavior Research Center at the UGR

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2. In the study, participants were presented with a series of images of food, some more appetizing than others (like hamburgers and fruit), and were asked how much money they would be willing to pay for it

Contact:

Raquel Vilar López

Departamento de Personalidad, Evaluación y Tratamiento Psicológico de la Universidad de Granada

Telephone: (+34) 958 242 948

E-mail: rvilar@ugr.es