Cleveland ? Eating just one meal high in saturated fat – in this case, carrot cake and a milkshake – can quickly prevent “good” cholesterol from protecting the body against clogged arteries, a small study shows.

The results of the research weren’t a surprise to the experts, but they say the findings reaffirm something that more people need to understand:

“What we put into our mouth makes a big difference in terms of our health,” said Dr. Charles McCauley, a cardiologist with Marshfield Clinic in Wisconsin, who reviewed the research but wasn’t involved with the study.

In the study, at The Heart Research Institute in Sydney, Australia, 14 people, ages 18-40, ate two meals of carrot cake and a milkshake one month apart. One meal was high in saturated fat – using coconut oil – and the other was high in polyunsaturated fat – using safflower oil.