(CBS) Eating a fatty fast food meal is never good for you, but scientists seem to have found something that's even worse: 

Eating fast food and then washing it down with a cup of coffee.

The caffeine actually doubles the elevation in blood sugar levels triggered by eating fatty fare, according to a new study published in the Journal of Nutrition. In fact, a coffee chaser can cause blood sugar levels similar to those seen in people at risk for diabetes.

"The results tell us that saturated fat interferes with the body's ability to clear sugars from the blood and, when combined with caffeinated coffee, the impact can be even worse," researcher Marie-Soleil Beaudoin said in a written statement. "Having sugar remain in our blood for long periods is unhealthy because it can take a toll on our body's organs."

Beaudoin, a PhD student at the University of Guelph in Canada, conducted the study with two professors at the university, Lindsay Robinson and Terry Graham.

In the first phase of the study, healthy men drank a specially formulated "fat cocktail." Six hours later, they got a sugary drink. The researchers found that the cocktail affected the body's ability to clear the sugar from the blood. The men's blood sugar levels were 32 per cent higher than they were when the men had not ingested the fat.