As if eating fat-laden fast food wasn’t bad enough, it now appears that topping off a fatty meal with a cup of caffeinated coffee doubles the damage the fat does to your body.

In the first study ever to look at the effects of saturated fat and caffeinated coffee on blood sugar levels, Marie-Soleil Beaudoin, a PhD candidate at the University of Guelph, found that blood sugar levels spike in healthy people after eating a fatty meal and drinking caffeinated coffee.

'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.'

Ten active, healthy men between 20 and 30 years of age were given a specially designed lipid beverage that had as much saturated fat as a cheeseburger, large fries, and a milkshake. This fat cocktail allowed researchers to accurately reproduce what happens to the body when fat is consumed. Each participant drank about one gram of the beverage for every kilogram of body weight. The test subjects were then given two mugs of coffee to drink five hours after consuming the fat cocktail, and an hour later they were given a sugary beverage.

When sugar is consumed, the body normally produces the hormone, insulin, which removes sugar from the blood and carries it to the cells of the body. The fat concoction consumed by the study participants apparently interfered with this process and increased blood sugar levels by 32%. After consuming the coffee followed an hour later by a sugary beverage, blood sugar levels were 65% higher. Calling the outcome unexpected, Beaudoin said that blood sugar levels spiked to pre-diabetic levels.

In a news release from the University of Guelph, Beaudoin stated, "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. Having sugar in our blood for long periods is unhealthy because it can take a toll on our body’s organs."

In addition to testing the study participants’ blood sugar levels, their incretin levels were also studied. Incretin hormones are released by the gastrointestinal tract after eating. They slow the rate of absorption of nutrients into the blood stream, and they also signal the pancreas to release insulin to move sugar out of the bloodstream.

The researchers found that after consuming the fat beverage, these hormones’ responses to carbohydrates are blunted, resulting in higher blood sugar levels. According to Beaudoin, this research suggests that fat and caffeinated coffee impair the communication between the gut and the pancreas which explains why the subjects could not clear sugar from their blood normally.

What is troublesome about this study’s findings is that the effects of a high-fat meal in the body may last for hours. You might want to reconsider the coffee and doughnuts for breakfast, or think of an alternative to the greasy, cheesy burger, large order of fries, and a coffee chaser for lunch.

The research was conducted with professors Lindsay Robinson and Terry Graham, and was published in the April issue of the Journal of Nutrition.