Fast Food Plus Coffee Equals Danger

If your guilty pleasures include a Quarterpounder with Cheese and hot coffee, the results of a study released in April 2011 offer a clear warning: don’t mix the two. A researcher at the University of Guelph discovered that drinking caffeinated coffee after eating a high-fat meal can nearly double the sugar spike that meal typically produces.

Marie-Soleil Beaudoin, a PhD student at the University of Guelph, conducted the study with two professors from the university. The group developed a novel “fat cocktail” that contains only lipids, to mimic what happens to the body when it ingests high levels of fat. Researchers gave the cocktail to one group of healthy men. A second group did not drink the cocktail, and a third group had the fatty drink and then drank the equivalent of 2 cups of coffee five hours later. All three groups were given a sugar drink six hours after the original meal.

The men who had drunk the fast-food equivalent but had no coffee showed blood sugar levels that were 32 percent higher than they were when they had not drunk the fatty meal first. When they drank caffeinated coffee after eating a high fat meal, their blood sugar levels were 65 percent higher than when they’d had neither fat nor caffeinated coffee.

Beaudoin said the study shows that the effects of a high-fat meal can last for hours and can affect how your body responds to food later in the day. In other words, that double quarter pounder with cheese can make it harder for your body to deal with the healthy food you eat for dinner.

The researchers also measured the hormones released by the gut to tell the pancreas to release insulin. They found that after ingesting the fat beverage, the hormone doesn’t respond as well to the presence of carbohydrates. Beaudoin concluded that fat and caffeinated coffee somehow impair the communication between the gut and the pancreas, and may be making it more difficult for the body to clear sugar from the blood. These findings are especially important for those at risk of type 2 diabetes.

Interestingly, while caffeinated coffee has been implicated in higher blood glucose levels in the short term, considerable research has also shown that those who drink caffeinated coffee on a regular basis have a lower risk of developing type 2 diabetes. The synergistic effect of caffeine and fatty foods, however, may offer a hint to researchers exploring the link further.


  1. the 4th paragraph is flawed, the fat was a controlled element and the study actually says that the coffee was what did it- and was there sugar in that “equivalent of 2 cups of coffee”?

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