A recent study has shown that a moderate level of carbohydrates may be better for controlling diabetes than conventional higher carbohydrate diets.
Diabetics eating a diet that partially restricted carbohydrates (about 45% calories from carbohydrates) achieved better glycemic control, had lower BMI’s and cholesterol, and were able to reduce diabetes medications compared to diabetics following a conventional, higher carbohydrate diet (about 55% calories from carbohydrates). HbA1c levels were also significantly improved.
The quality of the carbohydrate intake was not studied. Obviously a diet that contains 55% calories from carbohydrate might contain significant amounts of sugar. That level of carbohydrates is probably not too much if better food choices are made and an exercise program is being followed.