Caffeine: Does it affect blood sugar?

Short-term studies indicate that caffeine impairs insulin action but not necessarily blood sugar (glucose) levels in young, healthy adults. However, in individuals with 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. The amount of caffeine noted to have caused this effect was about 500 milligrams (or the equivalent of five cups of plain, brewed coffee) a day.

For individuals with type 2 diabetes who are struggling to control their blood sugar levels, limiting your caffeine intake may provide a benefit.