For obese people overeating is akin to drug addiction, research suggests.
Scans on seven overweight people revealed the regions of the brain that controlled satiety were the same as those in drug addicts craving drugs.
The US team who carried out the research said the findings could potentially help to uncover new treatments for obesity.
The work, led by a New York scientist, is published in the Proceedings of the National Academy of Sciences.
The researchers looked at brain impulses in seven overweight individuals.
They had all been previously fitted with a weight-reduction device called an implantable gastric stimulator (IGS).
The implant sends electronic signals to the vagus nerve which then relays messages of satiety to the brain, thus reducing the desire to eat.
To study the interaction between the stomach and the brain, the volunteers received two brain scans spaced two weeks apart, one when the implant was turned on and the other while it was switched off.
While the volunteers were feeling full and the implant was turned on, the scan revealed an increased metabolism in the hippocampus, an area of the brain associated with emotional behaviour, learning and memory, the orbitofrontal cortex and the striatum.
Lead researcher Dr Gene-Jack Wang, at the Brookhaven National Laboratory, New York, said: "As soon as we saw these scans, immediately it reminded me of what we had studied in drug abuse when people were under a craving situation - the same areas in the brain lit up."
He said this supported the idea that there were commonalities in the brain circuitry that underlay food intake and compulsive drug intake.
Although the study was small, he added, it would help to further understand the desire to eat and obesity.
"It gives us another channel to understand how to treat or prevent obesity."
Professor Jimmy Bell, of the molecular imaging group at Hammersmith Hospital, said: "This is a very interesting paper.
"There is a lot of research going on around the world looking for biomarkers - anything that will tell you directly what is going on in a biological process - to understand the relationship between appetite, satiety and emotional factors that control what we eat, and when we eat and how much we eat.
"I do not think it is surprising they have found a link between drug addiction and overeating. In a way you can think of eating as a 'necessary addiction' - if we were not addicted to eating, most of us would stop eating."