December 12/Montreal/University of Montreal -- While many may find enjoyment from eating fatty foods like ice cream and French fries, it can be quite difficult to remove them from our diet.

Researchers from the University of Montreal recently explored this difficulty and discovered that unhealthy food can trigger changes in brain chemicals before the onset of obesity. As such, it is possible that quitting a fatty or sugary habit can cause depression and withdrawal symptoms.

The team focused on researching biological reasons for obesity as well as associated diseases like type 2 diabetes, some cancers and depression. In particular, the scientists believe that going on a diet may sometimes feel like going through a drug withdrawal for individuals.

The research team from the University of Montreal’s Faculty of Medicine and the CRCHUM hospital Research Centre looked at one group of mice that consumed a low-fat diet (with 11% of calories made up fat) and another group that consumed of a high fat diet (with 58% of calories made up of fat). The study was conducted over a six-week period with the team of investigators monitoring how the various food types affected the mice.

Then, the scientists evaluated the relationship of food along with emotions and behavior with scientifically validated methods. They also examined how the brains of the mice changed in response to the food. The mice that had been on a higher-fat diet showed anxiety and their brains had been changed by their experiences.

“By working with mice, whose brains are in many ways comparable to our own, we discovered that the neurochemistry of the animals who had been fed a high-fat, sugary diet were different from those who had been fed a healthy diet,” noted Dr. Stephanie Fulton in the prepared statement. “The chemicals changed by the diet are associated with depression. A change of diet then causes withdrawal symptoms and a greater sensitivity to stressful situations, launching a vicious cycle of poor eating.”

In particular, the researchers explored the molecule dopamine and how it allows the brain to provide good feelings when rewarded. When the brain feels rewarded, it encourages individuals to pursue specific actions. This chemical is found in both mice and humans. The scientists explained how the CREB molecule manages the activation of genes that are involved in the functioning of the brain. The CREB also aids the formation of memories.

“CREB is much more activated in the brains of higher-fat diet mice and these mice also have higher levels of corticosterone, a hormone that is associated with stress. This explains both the depression and the negative behavior cycle,” continued Fulton in the statement. “It’s interesting that these changes occur before obesity. These findings challenge our understanding of the relationship between diet, the body and the mind. It is food for thought about how we might support people psychologically as they strive to adopt healthy eating habits, regardless of their current corpulence.”

The findings from the study were recently published in the online edition of the International Journal of Obesity. Funding for the project was provided the National Sciences and Engineering Research Council of Canada, the Canadian Diabetes Association, as well as the Research Council of Canada.