Typical behaviors of obese people?

Can eating become an addiction? There seem to be some parallels. The human brain of persons with obesity and persons with an addiction show an increased activity in specific brain areas as reaction to food or drug stimuli respectively.

Thereby, the blood and oxygen level increases in the amygdala, which is a brain area that is important for the perception of emotions such as fear, excitement, lust and reward. The reaction to food perceived as gratifying positive can lead to habitual overeating in the long term. Researchers of the IFB AdiposityDiseases at the University Leipzig also ascertained that the motivation to attain specific foods is especially in obese men unaltered high after eating.

German and Spanish researchers found similarities in the processing of reward stimuli in obese people and drug addicts. For this purpose, they evaluated numerous studies with participants who suffered either from obesity, a drug or behavioral addiction like compulsive gambling. In these studies the processing of reward stimuli in the brain was visualized using magnetic resonance imaging. The identified reactive similarities of food or drug stimuli may help to better understand the mechanisms of this disease and develop more effective therapies. The results of the analysis were published recently in the journal "Obesity Reviews" (12/2014).

Following up pleasant feelings

It is understandable that people want to repeat pleasant sensations and then act more and more habitual to achieve them. Those who eat regularly sweets to relax after a stressful day at work run the risk to develop a habit. Scientists from the IFB at the Max Planck Institute for Human Cognitive and Brain Sciences recently verified the hypothesis that there is a difference between normal and obese people in the tendency to habitual behavior. With the help of a computer test, 30 normal-weights and obese men in the age of 19 to 30 were tested, how much they make an effort to obtain a specific food. Obese participants were also motivated after having eaten this food to attain more of these snacks.

Interestingly, they noted in the accompanying written survey to be actually no longer interested in this food. From the contradiction between thinking and behavior in obese men, the scientists concluded that the unconscious, habitual eating behavior plays a role in developing and maintaining of obesity. Above all, the conclusion is that not only the conscious cognitive eating control needs to be addressed in obesity therapies, but increasingly also ingrained habits. Therefore, similar as in the so called mindfulness training, obese patients need to learn a new perception and awareness with respect to food and eating.

Doris Gabel

Publikations:
Horstmann A, Dietrich A, Mathar D, Pössel M, Villringer A, Neumann J.  Slave to habit? Obesity is associated with decreased behavioural sensitivity to reward devaluation. ("Appetite")
doi: 10.1016/j.appet.2014.12.212

García-García I, Horstmann A, Jurado MA, Garolera M, Chaudhry SJ, Margulies DS, Villringer A, Neumann J. Reward processing in obesity, substance addiction and non-substance addiction. ("Obesity Review")
doi: 10.1111/obr.12221