An international group of scientists has found that eating junk food could impact our immune system’s ability to fight disease.

Detailing their findings in a new study published by the journal Cell, the researchers, led by the University of Bonn, found evidence that our body’s defense system, reacts the same way to high-calorie foods packed with fats as it does to bacterial infections.

In other words, whenever we eat unhealthy and fatty fast foods, our immune system thinks that it must go into battle mode to fight off a disease.

The study found that the behavior of the immune system can remain quite active even after a switch to a healthier diet.

The researchers say long-term changes to the immune system may be involved in increasing the risk for arteriosclerosis, the hardening, and thickening of arteries, as well as diabetes and other diseases that have been linked to many Western diets.