If you’re having difficulty shedding those unwanted pounds, a new study may have a surprisingly simple reason for why that is. It may come down to stress, which scientists believe may be cancelling out any gains you have from eating a healthier diet.

Stress has long been pinpointed as the culprit behind health problems, but it may also cause your body to burn fewer calories, according to the research, which was performed by scientists at Ohio State University. The team found that women who ate a breakfast with lots of calories and healthy fat after a stressful event, the bodies burned fewer calories and raised indictaors in their blood that would be present if they had eaten a meal with bad fat.

The team compared women who ate breakfasts of biscuits, gravy, eggs and turkey sausage, with some having the meals made with palm oil, which has lots of saturated fat, while others ate it with monounsaturated sunflower oil, considered a good fat.

Women who ate the bad fat had higher blood markers for bad health indicators. Good fat lowers this inflammation, but after a stressful event, there wasn’t much difference.

“We know that a less-healthy meal is going to have adverse effects on markers of inflammation, but we wanted to look at this meal type with different types of fat,” said researcher Martha Belury, co-author of the study and a professor of human nutrition.

The statement adds: “It’s believed that reduced inflammation could be the cornerstone of the benefits of eating healthier foods such as the Mediterranean diet – one that is high in oleic acid, usually from olive oil, Belury said. Stressors raised levels of all four harmful blood markers in the sunflower oil group, but stress did not seem to budge the readings for those who ate saturated fat, Belury said.”