Some people really are addicted to foods in a similar way others might be dependent on certain substances, like addictive illegal or prescriptions drugs, or alcohol, researchers from Yale University revealed in Archives of General Psychiatry. Those with an addictive-like behavior seem to have more neural activity in specific parts of the brain in the same way substance-dependent people appear to have, the authors explained.
It's a bit like saying that if you dangle a tasty chocolate milkshake in front of a pathological eater, what goes on in that person's brain is similar to what would happen if you placed a bottle of scotch in front of an alcoholic.
The researchers wrote:
"One-third of American adults are now obese and obesity-related disease is the second leading cause of preventable death. Unfortunately, most obesity treatments do not result in lasting weight loss because most patients regain their lost weight within five years. Based on numerous parallels in neural functioning associated with substance dependence and obesity, theorists have proposed that addictive processes may be involved in the etiology of obesity.
Food and drug use both result in dopamine release in mesolimbic regions [of the brain] and the degree of release correlates with subjective reward from both food and drug use."
The authors believe that no studies had so far looked into the neural correlates of addictive-like eating behavior. They explained that some studies had demonstrated that photos of nice food can get the brain's reward centers to become more active in much the same way that photos of alcoholic drinks might do for alcoholics. However, this latest study is the first tell the food addicts from the just overeaters.
Ashley N. Gearhardt, M.S., M.Phil., and team looked at the relation between the symptoms of food addiction and neural activation. Food addiction was assessed by the Yale Food Addiction Scale, while neural activation was gauged via functional MRI (magnetic resonance imaging). Forty-eight study participants responded to cues which signaled the imminent arrival of very tasty food, such as a chocolate milkshake, compared to a control solution (something with no taste). They also compared what was going on while they consumed the milkshake compared to the tasteless solution.
The Yale Food addiction Scale questionnaire identified 15 women with high scores for addictive-like eating behaviors. All the 48 study participants were young women, ranging in BMI from lean to obese. They were recruited from a healthy weight maintenance study.
The scientists discovered a correlation between food addiction and greater activity in the amygdala, medial orbitofrontal cortex and the anterior cingulated cortex when tasty food delivery was known to arrive soon.
Those with high food addiction, the fifteen women, showed greater activity in the dorsolateral prefrontal cortex compared to those with low addiction to foods. They also had reduced activity in the lateral orbitofrontal cortex while they were eating their nice food.
The authors explained:
"As predicted, elevated FA (food addiction) scores were associated with greater activation of regions that play a role in encoding the motivational value of stimuli in response to food cues. The ACC and medial OFC have both been implicated in motivation to feed and to consume drugs among individuals with substance dependence.
In sum, these findings support the theory that compulsive food consumption may be driven in part by an enhanced anticipation of the rewarding properties of food. Similarly, addicted individuals are more likely to be physiologically, psychologically, and behaviorally reactive to substance-related cues."
"To our knowledge, this is the first study to link indicators of addictive eating behavior with a specific pattern of neural activation. The current study also provides evidence that objectively measured biological differences are related to variations in YFAS (Yale Food Addiction Scale) scores, thus providing further support for the validity of the scale. Further, if certain foods are addictive, this may partially explain the difficulty people experience in achieving sustainable weight loss. If food cues take on enhanced motivational properties in a manner analogous to drug cues, efforts to change the current food environment may be critical to successful weight loss and prevention efforts. Ubiquitous food advertising and the availability of inexpensive palatable foods may make it extremely difficult to adhere to healthier food choices because the omnipresent food cues trigger the reward system. Finally, if palatable food consumption is accompanied by disinhibition [loss of inhibition], the current emphasis on personal responsibility as the anecdote to increasing obesity rates may have minimal effectiveness."
"Neural Correlates of Food Addiction"
Ashley N. Gearhardt, MS, MPhil; Sonja Yokum, PhD; Patrick T. Orr, MS, MPhil; Eric Stice, PhD; William R. Corbin, PhD; Kelly D. Brownell, PhD
Arch Gen Psychiatry. Published online April 4, 2011. doi:10.1001/archgenpsychiatry.2011.32
Written by Christian Nordqvist