A new study has found that there may be a very simple reason behind why so many women struggle to keep the weight off, even with a better diet. A new study suggests that stress may be the culprit.

For the study, researchers tested women after they ate different meals, and found that the pressures a woman is facing may actually be more important than her diet in many ways, according to an Ohio State University statement.

So while these women may be looking for healthier ingredients in food and may in fact be eating better, stress may actually be interacting with the food they’re eating in an unexpected way.

“It’s more evidence that stress matters,” said Jan Kiecolt-Glaser, lead author of the study and a professor of psychiatry and psychology.

To come to their conclusions, scientists gave 58 women two different meals. One was high in saturated fat, while another was high in sunflower oil, a healthier fat. When women ate the saturated fat, inflammation levels were higher in blood tests, and they were lower after the healthier meal — not surprising.

But then scientists introduced stress. And they found that women who had a stressor the day before their meal, it didn’t matter what type of fat they ate — the inflammation levels were about the same.

“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.

“They’re not life-shattering events, but they’re not of the hangnail variety either,” Kiecolt-Glaser said.