social sciences

Can obesity be compared with addiction?

ice cream
Overindulging in foods with a high fat and sugar content such as ice cream can lead to obesity. Photo by: Renee Altrov.

People sometimes tend to overindulge in food just like in alcohol and drugs, but according to Uku Vainik, a research fellow of experimental psychology at the University of Tartu, it does not end here. His scientific article on the correlations between obesity and addiction was published in the journal Nature Human Behaviour.

Resulting from an extensive analysis of personality studies, it was found that the behaviour of an obese person is somewhat similar to that of an alcohol or drug addict. At the same time, obesity is a complex condition, which cannot be fully explained using a model of addiction.

The World Health Organisation estimates that the proportion of obese people has tripled since 1975. It has likely been driven by the increased availability of inexpensive high-calorie food. The loss of control some people experience with food, has led some scientists to the conclusion that obesity is caused by food addiction. However, others argue that food is one of the essential needs and does not contain the molecules of addictive substances like nicotine or caffeine do.

This debate prompted the research team of Dr Alain Dagher working at the Montreal Neurological Institute to find ways of assessing the behavioural similarities of obesity with addictive behaviour, but also with psychiatric disorders.

The leading author of this study, a research fellow at the University of Tartu, Uku Vainik, was also working at Dr Dagher’s lab as a postdoctoral fellow. Vainik decided to gather all the data from earlier studies, which associated obesity and addiction behaviour to personality traits.

The most common personality test NEO-PI (NEO Personality Inventory) measures 30 facets of the typical ways a person thinks, feels and behaves. These include self-confidence, altruism and impulsiveness. These facets are in turn used to evaluate the participant’s “Big Five” personality traits: agreeableness, extraversion, neuroticism, conscientiousness and openness to experience. “The correlations of the 30+5 personality traits with overweight are summarised by a personality profile, which can then be compared to the personality profiles of addictive behaviours, such as smoking, alcohol consumption and gambling,” said Vainik.

Scientists compared the personality profiles that were based on the data from 18,611 participants. They found that everyone’s addiction profiles were very similar, which indicates a large behavioural overlap. Furthermore, addictions had a behavioural similarity with uncontrolled eating. This similarity was due to similar associations with conscientiousness and anxiety.

Although obesity was also linked to addiction, this link was considerably weaker. To their surprise, scientists discovered that behaviourally, obesity overlaps more with mood disorders and personality disorders related to mood changes.

“Our study shows that addiction and obesity are similar in terms of impulsiveness and poor self-control. Therefore, using the methods for treating addiction in treating obesity might be useful and improve self-control,” said Dr Dagher.

He added that in treating obesity, the treatment should not focus on how addicts deal with sensation-seeking, because this personality trait is not linked to obesity. “We should take into account all the useful information about the similar traits of obesity and addiction, and then turn our attention elsewhere to get a comprehensive overview of the behavioural peculiarity of obesity.”

Vainik also notes that the label “food addiction” is used a bit too lightly. “We now have numerical confirmation for this,” he said and continued: “I understand that it is difficult for people to cope in our food-rich environment. But these challenges are not comparable to alcohol addiction. As long as our environment stays food-rich, we need to analyse our behaviour – relieve stress with other means and make our home environment health-friendly.”

The study was funded by Fonds de Recherche de Quebec, Canadian Institutes of Health Research and Estonian Research Council.

Find out more:

Read Uku Vainik’s Behind the Paper blog post in Nature Research.

Read Uku Vainik’s tweetorial about the paper.

Read the Nature News and Views article about the research.

Read the press release from McGill University.

The study was funded by Fonds de Recherche de Quebec, Canadian Institutes of Health Research and Estonian Research Council.

The translation of this article from Estonian Public Broadcasting science news portal Novaator was funded by the European Regional Development Fund through Estonian Research Council.

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