In one study, type 2 diabetics were randomly assigned to consume 1 cup (240 milliliters) of cranberry juice per day for 12 weeks, or a placebo drink. By the end of the study, blood sugar was significantly lower, and heart disease risk factors were improved, in the cranberry juice group compared to the placebo group.52
In another study, overweight, middle-aged, adults consumed either 2 cups per day of sugar-reduced cranberry juice for 8 weeks, or a placebo drink. Cranberry juice reduced fasting blood sugar, insulin resistance, blood pressure and inflammation, compared to placebo.53
As always, I would try to find a low-sugar or low-calorie variety, even if it’s artificially sweetened. Cranberry supplements or berries may also be effective.