The Irresistible Junk Food

Let’s take a look at the simple explanations of several landmark studies in the field of childhood obesity, many of which seem to point to the reality of the food addiction paradigm. Freelance journalist Bijal Trivedi specializes in scientific, environmental, and medical matters, and her work has appeared in every magazine you’ve ever heard of. She’s also a very accomplished international, Latin-style ballroom dancer, and a self-admitted ice-cream junkie. Trivedi compares sugar to cocaine, at least in its effects on the chemistry of her brain, or anybody’s:

There is now compelling evidence that foods high in sugar, fat and salt — as most junk foods are — can alter your brain chemistry in the same way as highly addictive drugs such as cocaine and heroin.

In Trivedi’s view, the food addiction paradigm is well on its way to becoming mainstream, as scientists uncover the biological mechanisms that make it possible. In fact, critics are thinking about legislation and lawsuits. They draw an analogy between the harm done by junk food, and the damage done by tobacco. They are encouraged by the successes that have been achieved in curbing advertising of alcohol products to minors.

Trivedi talks about two neuroscientists, Nicole Avena and Bartley Hoebel, who started looking into the food addiction issue back in 2001. Generally, if scientists want to know whether some behavioral phenomenon has a biological root, they try it out on lab animals, and the studies of childhood obesity are no different. The researchers’ attention became focused on the role of a brain sector called the nucleus accumbens, and a brain chemical called dopamine. Trivedi says,

Dopamine drives the pursuit of pleasure — whether it is food, drugs or sex. It is a brain chemical vital for learning, memory, decision-making and sculpting the reward circuitry.

Human studies also tell a story. Gene-Jack Wang, of Brookhaven National Laboratory, found that dopamine deficiency in the brain of an obese person shows up looking just like the dopamine deficiency in the brain of a drug addict. That seems pretty conclusive.

At the Oregon Research Institute, Eric Stice, another neuroscientist, compared brain activity in obese people and the lean people who presumably were not drug addicts. Trivedi writes:

In an as-yet-unpublished study he found that when fed milkshakes, lean adolescents with obese parents experienced a greater surge of dopamine — indicating a greater sense of satisfaction — than those who had lean parents. Stice suspects that this is where the problem begins. It is this innate enjoyment of food that primes certain people to overeat.

“Well, duh,” you might say, and you would be right. People overeat because they derive a great deal of enjoyment from that activity, and it didn’t start with McDonalds. Look at Henry VIII. He just plain liked to eat everything that didn’t run away, and he could afford to indulge himself.

As we all know by now, junk food, hyperpalatable food, and hedonic food all share a common characteristic — the presence of sugar, salt, and fat — in any combination. Paul Kenny of the Scripps Research Institute already knew all about the cocaine-addicted rats. There is a very detailed explanation of his work, investigating how rats handle a diet of junk food, and what it does to their brain chemistry. Here’s what happens:

In animals, as in humans, repeated cocaine or heroin use dulls the brain’s reward system. This leads to heavier use because the memory of a more pleasurable effect spurs the user to take more to get the same feeling, essentially chasing the high.

Trivedi talked with John Banzhaf, an attorney who took to court (and won) a case that makes TV and radio stations donate airtime for anti-smoking commercials. He thinks that maybe the fast food industry needs the same kind of restrictions as have been put on the tobacco business, especially in the area of its relations with children.

Your responses and feedback are welcome!

Source: “Junkie food: Tastes your brain can’t resist,” DrZarkov.com
Image by pterjan, used under its Creative Commons license.