For the animal study, Australian researchers divided mice into three groups. The first ate a normal diet, the second a high-fat diet, and the third a high-fat diet that contained a large amount of chlorogenic acid (CGA), a type of antioxidant found in coffee. Over the span of 12 weeks, the critters that ate the high-fat diet with CGA stored more fat and experienced increased glucose sensitivity and insulin resistance, precursors to type 2 diabetes, compared to the mice who ate a high-fat diet without the coffee compound. The results came as a surprise to researchers.
“Our hypothesis was that the coffee compound would reduce weight gain and improve insulin sensitivity,” says study co-author Kevin D. Croft, PhD, of The University of Western Australia School of Medicine and Pharmacology. ”Clearly this is not the case.”
Don’t break things off with Joe just yet, though. The mice in the study consumed doses of CGA equivalent to drinking five or six cups of coffee per day, says Croft. Previous research has shown that consuming CGA in moderation can reduce blood pressure, increase insulin resistance, and—here’s the kicker—even prevent weight gain. While researchers are unsure why the opposite is true at high doses, they believe that excessive CGA intake may hinder the body’s ability to process and use fat.
To reap coffee’s health benefits without increasing your poundage, limit yourself to three or four cups of coffee a day, says Croft. Keep in mind, though, that a cup is eight ounces. Suck down a Trenta from Starbucks, and you’ve already hit your max for the day.