Coffee has yet again been shown to be an effective part of preventing diabetes. Coffee had a bad rap for a long time, likely because it was associated with other behaviors like coffee (for breakfast!) and smoking. However, the studies I have come across recently have shown that coffee lowers the risk. Decaffeinated is not effective and the coffee is best taken around meals.
A few other tips. Watch the creamers. Most are evil and contain hydrogenated oils, which will promote diabetes. Consider soy or coconut based creamers, which do not contain these hazards.
NO ARTIFICIAL SWEETENERS!! Period. Try honey or stevia instead (honey is the preferable sweetener).
We have an esspreso machine here at the office. As barista in charge of mochas, I make a double shot of esspreso w/ Ecuadorian cocao, cinnamon, ice and top it off with some form of chocolate almond / rice / soy / hemp / hazelnut milk. Probably about 80 calories but loaded with high quality phytonutrition.