High-fat diet may damage weight-regulating process in the brain, increasing type 2 diabetes risk

Many overweight individuals have had the experience of trying unsuccessfully to lose weight. This contributes to the obesity epidemic that is putting millions of people at risk for developing type 2 diabetes.

Now, a new study suggests that the reason for this difficulty is damage to key areas of the brain caused by an unhealthy diet.

The University of Washington researchers who conducted the study said that their findings may not only shed light on why some people have such difficulty losing weight, but also explain the consequences of eating a high-fat diet.

For the study, the investigation team fed a group of laboratory mice a high-fat diet for several weeks. The type of feed was meant to mimic the fat content of a typical Western-style diet. During the course of the study, the researchers performed various sorts of imaging techniques on the brains of the mice to determine what, if anything, happens to the organ during periods of high fat consumption.

The results of the analysis showed that the mice developed inflammation in the brain region known as the hypothalamus. This area of the brain plays a key role in regulating how the body stores fat. In response to this inflammation, the researchers noted that brains of the mice started a reaction known as gliosis.

During gliosis, glia and microglia cells accumulate in areas of the brain that have been damaged. It is believed to be the brain's wound-healing process. In the case of the mice fed a fatty diet, it appeared that it was responding to damage in the hypothalamus.

However, the researchers discovered that the process of gliosis subsided over time, even though the mice continued to consume fatty foods and experience inflammation in the hypothalamus.

This prompted the team to speculate that a high-fat diet causes inflammation in the brain that damages key weight-regulating structures. The brain's response to this attack is unable to keep pace with the damage.

Joshua Thaler, MD, PhD, the leader of the study, said that the findings could have important implications for the treatment of obesity and its related complications, including type 2 diabetes. By preventing the inflammatory process in the hypothalamus from beginning, it may be able to stop the damage that occurs to this important weight-regulating area.

"If new medicines can be designed that limit neuron injury during overeating, they may be effective in combating the obesity epidemic," he said.

Doctors commonly recommend weight loss as the most effective way for an individual to reduce their type 2 diabetes risk. However, this is exceedingly difficult for the majority of people. It was generally assumed that it was simply difficult for people to keep up a healthy diet and exercise regimen over the long term, but these findings suggest that the problem may go deeper.

If researchers are able to develop a medication that prevents the brain damage associated with a high-fat diet, it could significantly reduce the burden of type 2 diabetes.