Coffee has a number of health benefits, and some studies suggest the drink may even help prevent type 2 diabetes: For example, a study published in March 2014 in Diabetologia found that those people who increased their coffee consumption by more than one cup per day over a four-year period had a lower risk of type 2 diabetes. In the analysis, each additional cup of coffee per day was associated with a 5 percent lower risk of type 2 diabetes. A review published in February 2014 in the European Journal of Nutrition supports this notion: Data in the paper suggested that, in nonsmokers who were slightly overweight or had a healthy weight, the risk of type 2 diabetes dropped by 12 percent for every two cups of caffeinated coffee they drank per day.
But the benefits of drinking coffee if you already have diabetes are less clear: A review published in January 2013 in the Journal of Human Nutrition and Dietetics cites some research that suggests caffeine may increase glucose concentrations and reduce insulin sensitivity.
“Coffee may have different effects on different people, along with other factors that can affect blood sugar levels like medications, food intake, and activity level,” Matteo explains. “People with diabetes may need to do some self-experimentation to determine how coffee affects their blood sugar levels.” For instance, if you notice that your blood sugar levels spike after you drink caffeinated coffee, trying switching to decaf, she says.
Regardless of whether you’re looking to prevent or control diabetes, go easy on the added sugar and flavored creamers when drinking coffee, as you may be unintentionally reducing the health benefits in your mug. “I can’t tell you how many times people say, ‘I don’t put sugar in my coffee,’” Matteo says — but then reveal that they’ve been adding vanilla or hazelnut creamers. When we consume concentrated sweets, especially in liquid form, we tend to see a rise in blood sugar levels quickly, Matteo adds. That’s because the sugar in liquids is able to enter the bloodstream more quickly than the sugar in foods.