People can become addicted to eating for its own sake but not to consuming specific foods such as those high in sugar or fat, new research suggests.
Edinburgh University scientists found no strong evidence for people being addicted to the chemical substances in certain foods.
They found the brain does not respond to nutrients in the same way as it does to addictive drugs such as cocaine.
However, people can develop a psychological compulsion to eat.
This is driven by the positive feelings that the brain associates with eating, the researchers said.
The study, which examined the scientific evidence for food addiction as a substance-based addiction, is published in Neuroscience and Biobehavioral Reviews.
The scientists said it was a behavioural disorder and could be categorised alongside conditions such as a gambling addiction.
They suggested tackling the problem of obesity should be moved away from food itself and instead focussed on the individual's relationship with eating.
The researchers also said the current classification of mental disorders, which does not permit a formal diagnosis of eating addiction, could be redrawn.
However, more research would be needed to define a diagnosis, the scientists said.
The work was carried at the Universities of Edinburgh, Aberdeen, Gothenburg, Essen, Utrecht and Santiago de Compostela.
The researchers are involved in the NeuroFAST consortium, which is an EU-funded project studying the neurobiology of eating behaviour, addiction and stress.
Dr John Menzies, research fellow in Edinburgh University's centre for integrative physiology, said: "People try to find rational explanations for being over-weight and it is easy to blame food.
"Certain individuals do have an addictive-like relationship with particular foods and they can over-eat despite knowing the risks to their health.
"More avenues for treatment may open up if we think about this condition as a behavioural addiction rather than a substance-based addiction."
Prof Suzanne Dickson, of Gothenburg University and co-ordinator of the NeuroFAST project, said: "There has been a major debate over whether sugar is addictive.
"There is currently very little evidence to support the idea that any ingredient, food item, additive or combination of ingredients has addictive properties."