According to researchers, the view that neurobiological concepts related to addiction could help explain obesity is gaining consensus among those working in the field – a view that is being challenged by this review.
This ‘food addiction model’ works on the basis that certain foods – usually processed goods – may be addictive. They are claimed to act on the brain to shape behaviours in a similar way to drugs of abuse, which is linked to behavioural, addictive traits that exist in a select group of obese people.
However, to find out how relevant the food addiction model is to obesity, the authors reviewed several key areas of evidence.
First, they looked at the clinical overlap between obesity and drug addiction. While there were “some similarities in patterns of behaviour”, they found “It is very difficult to apply the criteria used in defining drug addiction to the task of defining food addiction.”
Binge-eating disorder
They pointed out that, unlike drugs, food is necessary for survival and easy to obtain. The authors found that clinical overlaps were most apparent when looking at people with binge-eating disorder (BED). People with this disorder shared many behaviours with people addicted to drugs, including loss of control of eating, escalating consumption, and compulsivity.
A second line of evidence analysed was family studies, which hint at shared genetic susceptibilities between obesity and substance addiction. However, the authors argued that the underlying processes might not necessarily be the same in both conditions.
The authors also reviewed the neurobiological evidence for food addiction.
While it has been suggested that obese people’s brains have reduced dopamine binding – dopamine is a chemical involved in reward and addiction – the results of studies in this area were very complex and did not support an addiction model, they claimed.
Brain responses
Functional imaging studies have also looked at altered brain responses to food-related stimuli among the obese. However, results have been variable and inconsistent here, too.
The authors proposed that overeating might be too complex to get a consistent result from these studies, and that the many genetic and environmental factors which contribute to obesity needed to be considered in future.
While concluding that the food addiction model currently had limitations for studying obesity, the authors were not wholly negative about the model.
They argued that it could be potentially useful for understanding and treating obesity if it were made more sophisticated and precise in future to take into account “the complexity of this condition”.