Key to this pathway are star-shaped cells in the brain called astrocytes, which normally react to a lot of fat and calories being consumed by putting the brakes on food intake, balancing out what's ingested.

"Over time, astrocytes seem to desensitize to the high-fat food," says Kirsteen Browning, a professor of neural and behavioral science at Penn State College of Medicine.

"[After] around 10-14 days of eating a high fat/calorie diet, astrocytes seem to fail to react and the brain's ability to regulate calorie intake seems to be lost.

As well as recording food intake and body weight, the team also used genetic editing techniques to target and monitor specific neural circuits, including the astrocytes.

By inhibiting astrocytes in the brainstem, the researchers were able to link these cells to reduced gut-brain communication and lack of food intake regulation that would normally occur during the first 3-5 days of being on a high-fat diet.

The researchers are hoping that by discovering more about the "complex central mechanisms" behind the brain's response to over-eating, we'll be able to develop ways to target them and reduce obesity in the future.