What is energy balance

Obesity: How does the brain react?

Why does obesity make us sick? What happens in the brain when you are overweight?

A group of nerve cells in the brain is now suspected of making overweight mice sick. A research team from the Max Planck Institute for Metabolic Research in Cologne found that these nerve cells in obese mice worsen the metabolism in the liver even further, driving the blood sugar level up further and thus triggering a vicious circle.

According to the Federal Statistical Office, more than half of all Germans are overweight and the number of type 2 diabetes is also increasing sharply. This disease is a typical secondary disease of overeating and lack of exercise. Diabetes is triggered by a disruption of the insulin metabolism. This makes body cells insensitive to this hormone, which is produced in the pancreas and which regulates blood sugar levels.

A research team from the Max Planck Institute for Metabolism Research wants to understand how obesity occurs and how the body maintains the balance between food intake and energy consumption. Not only are the fatty tissue and muscles responsible for this, but also the brain. “We're examining the hypothalamus, an area in the brain that regulates hunger and satiety. More precisely, let's look at different types of nerve cells and their role in this complex system of body weight regulation, ”explains Dr. Christine Hausen, scientist in the department of Director Prof. Dr. Jens Brüning.

A vicious cycle makes overweight mice sick

In the latest study, the scientists examined the group of MCH nerve cells. These get their name from "melanin-concentrating hormone (MCH)", a messenger substance in the brain that is important for food intake and energy balance. “Overweight mice have high levels of insulin, including in the brain. In the MCH nerve cells, in contrast to other nerve cells, we observe that these are activated by the insulin when they are overweight. You remain sensitive to insulin, ”explains Hausen. These nerve cells, which are permanently activated when overweight, also contribute to a disturbed sugar metabolism in the liver. The liver produces sugar in an uncontrolled manner, which further increases blood sugar levels and leads to progressive deterioration in health. As a result, the insulin levels remain high and the MCH nerve cells remain activated. “It's like a vicious circle. This only derails the metabolism even more, ”says Hausen.

In fact, obese mice, in which the MCH nerve cells have been modified in such a way that insulin cannot work in them, are better off. Hausen is critical of an application in medicine: “The brain's reaction to obesity is very complex. Different groups of nerves respond differently to insulin. In order to actually be able to intervene with medication, we have to understand the whole system even better. We are continuing to work on that. "