Research has shown that cutting back on foods high in fat does indeed help us lose weight. However, cutting back is often not that easy. A study published in the latest issue of the International Journal of Obesity has found that ending your fatty food habit can often cause feelings like drug withdrawal and depression, explaining why it is so hard to quit eating poorly and why so many are stuck in a cycle of binge-eating and fad diets.

"The chemicals changed by the diet are associated with depression," said Stephanie Fulton, one of the study authors, in a statement. "A change of diet then causes withdrawal symptoms and a greater sensitivity to stressful situations, launching a vicious cycle of poor eating."

The study was conducted by researchers from the University of Montreal on mice. Half of the mice were fed a high-fat diet, with fat consisting of 53 percent of their dietary calories. The other half were fed a low-fat diet, the fat amounting to 11 percent of their daily calories. Though the increased amount of fat caused the high-fat group of mice to expand their waistlines by 11 percent, they were not yet obese.

However, their diets had already taken a toll on their brains and behavior. The high-fat group exhibited more signs of anxiety than the low-fat group. The high-fat group also had greater amounts of CREB, a molecule that is instrumental to the production of dopamine and the formation of memories, and stress. Researchers say that these changes in the brain explain increased feelings of depression and of negative behavior.

"This explains both the depression and the negative behaviour cycle," Fulton explained. "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."