Is America’s obesity problem really a problem of addictive behavior?
By Barbara Kessler
Green Right Now
Could it be that Overeaters Anonymous got it right? That our modern love of fatty, sugary foods is not just a fleeting affair but a fatal attraction – or more precisely, an addiction?
If this were the case, it would place America’s obesity problem in a whole new light, one that cries out for solutions to help people avoid slipping into an addictive behavior that leads to a host of medical problems, from heart disease to diabetes.
In a study published Sunday in the online journal Nature Neuroscience, researchers at Scripps Research Institute in Florida, looked at the biological underpinnings of unhealthy eating by giving lab rats unlimited access to high-fat, high-sugar foods.
The rats settled into a pattern of snacking on these foods — Ding Dongs, cheesecake, frosting, pound cake, bacon and sausage – throughout the day. And their weight ballooned.
By contrast, rats given only occasional “tasty” treats, did not become obese; nor did the control rats that were maintained on the diet of balanced nutritional food they’d been raised on.
The obese rats quickly exhibited two hallmark features of addiction, said researcher Dr. Paul J. Kenny of Scripps. First, they displayed a “crash” of their brain reward network. Specifically, their pleasure receptors became overwhelmed by the constant influx of excessively satisfying sweet and high-fat treats, causing a breakdown in the system.
This is akin to what happens to those (people and rats) who become addicted to drug substances; their brains demand more and more of the pleasure-producing substance to receive the same effect. Hence, the rats began to overeat.
The second way in which the rats acted like addicts was that they were undeterred by a “negative stimulus” – the threat of a minor electric shock to the foot – in seeking out their fatty and sweet foods.
Furthermore, when the rats were re-introduced to healthy food, they refused to eat it. It was almost as if they had become adverse to the food they’d been raised on, Kenny said.
This sort of behavior has been demonstrated in other studies, the associate professor said. But it was still shocking to witness. “I was surprised with the magnitude of the effect,” he said.
“They voluntarily starved themselves. They didn’t want to eat that anymore. They wanted their cheesecake and Ding Dongs,” Kenny said.
The rat study was set up to replicate the situation Americans face – having virtually unlimited access to sweet, fatty foods. And it has clear ramifications for policy makers as well as those who are obese.
The Scripps research team, lead by Kenny and graduate student Paul M. Johnson, expects to continue its work, looking next at the neurobiology of why the rats did not want to shift back to the healthier food (they did eventually when the treats were withdrawn longterm). This field of endeavor could help point the way for millions of Americans who find themselves “hooked” on unhealthy food.
“If you’d rather starve than eat a salad,’’ Kenny said. “That’s got huge implications for people who are trying to diet and lose weight.”
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