April 5, 2011 -- The brains of people with food addiction appear to behave like those of people with dependence on alcohol or drugs, according to new research.
''People who report symptoms of addictive-like eating behavior also appear to show the same pattern of brain activity as we would see in other addictions," says researcher Ashley N. Gearhardt, a clinical psychology doctoral student at Yale University.
Her study is published online in the Archives of General Psychiatry.
The researchers believe the study is the first to link addictive eating with a specific brain activity pattern.
The study results suggest that some obese people may be better served with addiction treatment than with traditional obesity treatments, says Mark Gold, MD, an addiction expert at the University of Florida, Gainesville, who reviewed the study results for WebMD.
Food Addiction and Brain Activity
With one-third of American adults obese, Gearhardt and her colleagues wanted to explore the theory that addictive processes may be involved in the development of obesity.
For the study, the researchers did a complete evaluation on 39 women, average age about 21. Their average body mass index (BMI) was 28 (25 and above is termed overweight). They ranged, however, from lean to obese. All had enrolled in a program to help people get to and maintain a healthy body weight.
The researchers used the Yale Food Addiction Scale to measure addictive eating and gave each woman a score. The scale has 25 items and asks about eating behaviors such as loss of control.
Next, the researchers used functional MRIs (fMRI), which are capable of measuring tiny metabolic changes that take place in the active parts of the brain.
The fMRIs were done when the women drank a tasty chocolate milkshake and a tasteless drink. They were also done when the women were shown pictures of the milkshake and a glass of water.
When the women looked at the picture of the milkshake, the food addiction scores correlated with greater activation in areas of the brain that help encode the motivational value of certain stimuli in response to food cues. Activation in these areas has been linked to food cravings, for instance, Gearhardt tells WebMD.
In response to their anticipation of food, women with the higher food addiction scores, compared to those with lower scores, had more activity in two areas of the brain. These two areas are involved in decision-making, control of behaviors, and learning relationships between stimuli and responses.
When drinking the milkshake, women with higher food addiction scores showed less activation in the area of the brain that is concerned with being able to inhibit a behavior. It indicates these women were less able to control their actions.
The brain patterns found in people with high addictive food scores, Gearhardt tells WebMD, are very similar to what is seen with other addictions.
"For people who are saying, 'I feel addicted to food, I can' stop,' the same brain patterns appear to be involved," she says.
No link was found between the scores on the test and body mass index. Some lean women had high scores. Gearhardt says that suggests evaluating food addictive behaviors in lean people may help identify those at risk for later weight gain or eating problems.
The study is an important one, says Gold, who is the Donald R. Dizney Eminent Scholar and Distinguished Professor at the University of Florida.
"There is a considerable amount of controversy about what a food addiction is," he says. "One of the reasons this study is so important is they are correlating findings with brain changes rather than someone's belief." The new research used a validated scale to assess the addiction objectively, he says.
To him, the bottom line of the new research is this: "The more food addicted, the more likely you are to have changes in the brain that look as though you are on a drug."
The study may help explain why some obese people who obtain treatments that focus on the physical -- such as weight loss surgery -- aren't helped, Gold tells WebMD.
For those who are food addicted, paying attention to food cues is crucial, Gearhardt says. "Monitor what triggers for you your out-of-control behavior.”
Changing your environment in a food-obsessed society is difficult, she says, but not impossible. If driving past your favorite bakery on your way to work is too much temptation, for instance, find a new route to work, she says.