Eating an unlimited amount of high-fat food for 6 weeks before returning to a normal diet causes anxiety, addiction, and other similar symptoms in mice.

Rodents also experienced chemical changes in the brain that allowed parallels between the way the brain responds to fatty and sugary foods and the way it responds to drugs such as cocaine. Together, new research findings have added more clarity to the body’s habituation to unhealthy foods. 

Over the past decade or so, a growing body of research has begun to suggest that certain types of food may indeed be addictive. Rats that were cyclically banned from sugar or fat and given free access to them showed intense signs of thirst. Once they become addicted, rats will go to great lengths to get foods rich in sugar or fat.

Some of the first studies in this area only showed that when the sugar was removed from the rats, the animals went through all the withdrawal symptoms, including anxiety and depression. Subsequent work showed that these symptoms are accompanied by changes in the dopamine and opioid systems, which are neurotransmitters involved in the formation and removal of addiction.

After the mice were put on a healthy diet, they showed some signs of apathy and anxiety. At the same time, they were very active trying to get some sugar.

Scientists hope that the results of these studies will make people think about what they eat and whether they have any dependence on certain foods.