It's called the Dawn effect. It's when your liver kicks out sugar. Also there was a study done on the effect of coffee on your blood sugar. My endocrinologist told me it takes a unit of insulin for every cup. It's from the coffee not anything you add to it. He said they don't know why but that's the effect.

I had to give it up completely. It was keeping me between 200 and 250 until I tested before lunch and took insulin to correct it. Even though you are not using insulin your body does the work for you and you absorb excess sugar from the coffee you are drinking. As we know insulin is the hormone that makes us store excess sugar as fat.

It definitely made a difference for me. I am type 1 and PCOS.