1 OPINION. 2  The screening process for Syrian refugees is much more rigorous than for other visitors coming to the U.S. (AP Photo/Hassan Ammar)
About 250 milligrams of caffeine â or the equivalent of 2 to 2 1/2 cups (473 to 591 milliliters) of plain, brewed coffee â a day may cause this effect. If you have type 2 diabetes and you're struggling to control your blood sugar levels, limiting the amount of caffeine in your diet may provide a benefit.
Slightly, but it does. Specially in persons with Type 2 diabetes. Caffeine: Does it affect blood sugar? Caffeine impairs insulin action, but doesn't necessarily affect blood sugar (glucose) levels in young, healthy adults. However, if you have type 2 diabetes, the impact of caffeine on insulin action may be associated with a small, but detectable rise in blood sugar levels, particularly after meals.