Is TV making you fatter?

Ash Venkat, In-Depth Editor
April 16, 2010
Filed under In-Depth

While the mindless crunching of potato chips may seem harmless, scientists are now trying to put their fingers on what it is that makes a supposedly small snack into an empty bag of chips. They are classifying this habit as an addiction: a loaded term that connotes illegal substances, hospital visits, pain and even death. However, this form of addiction refers not to heroin or cocaine, but to something that appears more innocent – junk food.

Recent studies have shown that nearly the same processes that occur in a brain addicted to heroin also take place in a brain accustomed to junk food. Each substance triggers the release of the chemical dopamine, which causes feelings of pleasure and happiness, to be released in extraordinary amounts. In order to compensate for this, the brain releases less dopamine for everyday activities, meaning that in order to feel happiness, indulging in junk food becomes a necessity.

Unfortunately, addiction is also a vicious cycle, as eventually the dopamine receptors in the brain need more and more junk food in order to receive the same high. With junk food addiction, this means that the more junk food you eat, the more you want to eat, often causing an addict’s weight to spiral out of control.

The Scripps Research Institute, which is based in Florida, explored the realities of junk food addiction in an experiment involving rats. One group was fed a high-calorie, high-fat diet consisting of unhealthy foods including bacon, pound cake and candy bars. These rats quickly gained weight. In order to demonstrate the addictive properties of junk food, the scientists began to give the rats a harmless but extremely uncomfortable electric shock to the foot when the rats ate unhealthy food. However, these rats ignored the shocks and kept on eating.

On the other hand, the rats who were fed the equivalent of a healthy diet for humans did not overeat and would stay away from unhealthy food when they were shocked. In addition, when the rats that were fed junk food suddenly had their diets changed to healthy food, they simply refused to eat for nearly two weeks. The theory behind this is that their brains’ pleasure centers had been so overstimulated by the junk food that the healthy food held no appeal for them.

When the Scripps Research Institute compared the brains of the rats that fed junk food to those that were fed healthier foods, they found that the unhealthy rats’ dopamine receptors had declined in a manner similar to that in cocaine and heroine addictions, leading the group to assert that junk food is as addictive as illegal drugs.

One theory as to why junk food is so addictive has been linked to human evolution. For the better part of human history, foods that were high in sugar and fat were very difficult to come by and held valuable nutrients. Thus, the brain would reward people heavily when they took these in. However, in today’s world of processed food where sugar and fat are all too available, the brain has not yet caught up.

Some believe that people can overcome their junk food addictions by staying away from high-fat, high-calorie foods until their self-discipline is good enough to keep their food habits under control. Fortunately, this is an addiction that once controlled, does not mean the former addict cannot enjoy a bag of chips every once in a while.