Junk Foods Trigger Food Addiction in Obesity?Tuesday, March 30, 2010
Readers of these pages will be quite familiar with my previous posts on food addiction.
A new paper by Paul Johnson and Paul Kenny from the Scripps Research Institute, Jupiter, FL, just released online in Nature Neuroscience, demonstrates that in rats development of obesity is coupled with a progressively worsening deficit in neural reward responses (as seen in cocaine or heroin abuse).
In drug users, this decreased neural reward response is considered crucial in triggering the transition from casual to compulsive drug-taking.
In their experiments, the researchers found compulsive-like feeding behavior in obese but not lean rats, and showed that this compulsive overeating was even resistant to disruption by an aversive conditioned stimulus.
The researchers also found down regulation of dopamine D2 receptors in the striatum (an area of the brain involved in reward behaviours) in a manner similar to what has been reported in humans addicted to drugs.
Genetic knockdown of striatal D2 receptors also rapidly accelerated the development of addiction-like reward deficits and the onset of compulsive-like food seeking in rats with access to palatable high-fat food.
Together these data clearly demonstrate that overconsumption of highly palatable foods can trigger addiction-like neuroadaptive responses in brain reward circuits that can drive the development of compulsive overeating.
As I noted in several media interviews on this article yesterday,
“while not all forms of obesity can be reduced to food addiction, anyone dealing with obesity needs to be aware of the possibility that they may be addicted to certain foods and must therefore approach their obesity in the same manner as they would approach any other addiction. Unfortunately, in contrast to substance abuse, food abstinence is not an option“.
I can certainly now see why diet plans for treating food addiction are about as successful as drinking plans are for managing alcoholism.