# Brain Signal Found That Can "Force" the Body to Lose Fat

Scientists at Washington University School of Medicine have discovered that a specific signal from the brain, linked to the hormone leptin, can trigger active fat burning in bone marrow and other "stubborn" areas. Notably, food intake can remain unchanged. The findings have been published in the journal Nature Metabolism (NatMet).

The researchers focused on a special group of fat cells located deep within bone tissue. In adults, up to 70% of bone marrow consists of adipose tissue that is virtually unaffected by diets and physical activity. These cells—known as constitutive bone marrow adipocytes—produce elevated levels of proteins that prevent fat breakdown, which is why they are considered metabolically "resistant."

During experiments on mice, prolonged administration of leptin directly into the brain led to notable metabolic changes. The animals showed reduced glucose and insulin levels, decreased activity of proteins that suppress lipolysis, and within just a few days experienced nearly complete loss of fat reserves. Remarkably, the subjects' diet remained unchanged throughout.

The study authors caution that the identified mechanism has a powerful effect and requires a careful approach. "Stable" fat cells are located not only in bone marrow but also in the hands, feet, and around vital glands. In severe diseases accompanied by wasting, excessive loss of such fat may increase fracture risk and negatively impact quality of life.

According to the scientists, a deeper understanding of this process may contribute to developing new methods for preserving adipose tissue in patients with cachexia—a severe form of wasting associated with chronic diseases. At the same time, controlled influence on "resistant" fat depots may in the future become the basis for developing innovative obesity treatment strategies.