After meals, their blood sugar rises higher than normal and caffeine may make it tougher to bring it down to a healthy point.
This could lead to too high blood sugar levels which overtime, may rise their chance of diabetes complications including nerve damage or heart disease.
Scientists also believe caffeine can affect a type 2 diabetic in other ways including raising levels of certain stress hormones, like epinephrine (also known as adrenaline).
Epinephrine can prevent the cells from processing as much sugar and may also prevent the body from making as much insulin.
Source: Daily Express