Studies have found that rats that are addicted to a unhealthy diet of junk food, will die of starvation rather than return to healthy eating habits.

The journal, Nature Neuroscience, published a three-year study where Scripps Florida scientists, Paul Johnson and Paul Kenny have demonstrated that a rat's response to limitless amounts of junk food imitates the patterns of drug addictions, to include the changes that take place in brain chemistry.

Kenny stated, "What we have are these core features of addiction, and these animals are hitting each one of these features."

During the initial study, the rats were fed either a balanced diet or an identical diet plus limitless junk food bought at supermarkets, these foods included processed lunchmeats and cakes. In a relatively short amount of time, the rats eating the diet of junk food ate obsessively and rapidly gained weight.

Kenny found that the junk food rats were, "taking in twice the amount of calories as the control rats."

Rat Food Addiction Mimics Drug Addiction

The rats that ate compulsively were hypothesized because, like those addicted to drugs, the rats began to need to consume larger amounts of the junk food to reach the same amount of pleasure.

Recreational drugs stimulate a person's brain pleasure areas, especially the D2 which is the dopamine receptor. When this receptor is overly stimulated, it causes the body to produce less dopamine and the person needs more of the drug to get the same the repeated effect.

Pleasurable activities like food or sexual activity can release dopamine, so both Kenny and Johnson hypothesized that food has the same effect. The rats from the initial study had their brains attached to a device that would stimulate the D2 receptors as they ran on a wheel. This test would show if the rats had adapted to the dopamine.

The rats on the junk food diet ran on the wheel notably longer than the rats eating a normal diet. This indicates that the junk food rats' receptors had become desensitized. This desensitization happened after only five days of eating the unhealthy diet.

Kenny explained it this way, "They're not experiencing rewards the way they should," he said, "When you experience that, one way of feeling better is to go back on the junk food; They lose control. This is the hallmark of addiction."

The researchers conducted a second test of their addiction theory. They blocked the D2 receptors in the healthy rats by using a virus, and those rats, too, began to eat obsessively.

Johnson stated that their findings, "is the most complete evidence to date that suggests obesity and drug addiction have common neurological bonds."

What Research Shows Concerning Food Addiction

Once they found that rats had become addicted to the junk food, the researchers wanted to discover how far the addiction would go. To find out, they used both the addicted rats and the rats that ate healthy food and gave them an electric shock when they ate the junk food. The non-addicted rats ceased eating the junk food, while the addicted rats continued to ignore the shocks and eat the junk food.

What stunned the researchers most was that the junk food rats refused to eat for about two weeks when their junk food was replaced with the healthier rat chow. Kenny said, "They actually voluntarily starved themselves…Their dietary preferences are dramatically shifted."

From this research, one can learn that some humans also deal with addiction to junk food. Since not all humans that have access to junk food don't become obese, Kenny believes the difference lies with humans knowledge concerning health and social stigmas that moderate humans eating habits. "The rats don't suffer from the same social pressures that we do," Kenny said.

Nutritionist Sandy Livingston states, "Certainly, we see this addictive pattern in humans. They know they shouldn't overeat, but they do it anyway." Livingston stated that she hopes that the biochemical part of addiction to food may result in less guilt and judgment that goes along with obesity. "A lot of people blame themselves -- 'Why don't I have any willpower?'" Livingston said.

Jordan Rubin, author and nutritional supplement manufacturer, said "Food can be highly addictive. When people describe overeating and weight loss as a battle, this is why." He believes more research is needed to discover which specific components of junk food, such as MSG, might make it addictive to humans.

Kenny stated he hopes for a better understanding of the biochemical that causes an addiction to food may help in the development of a vaccine or drug to help those who are compulsive eaters. Maybe it would be better if people find out their food sensitivities (which can cause biochemical reactions and food addictions) and avoid those foods!