Is a high Glycemic Index diet essentially the same thing as the diabetic exchange diet?

No, they are very different plans. The diabetic exchange diet is an archaic system where various amounts of foods were assigned an “exchange” value. 1 exchange of breads/starches were estimated at 15g of carb (1 small potato, 1 slice of bread, 1 small brownie), etc. The problem is that the foods we eat don’t often fit these 15g amounts (most breads are 17-20g of carb per slice), so you ended up with very inaccurate carb estimations.

The glycemic index assigns values to various foods based on how quickly they are metabolized and their impact on blood glucose. Also very inaccurate and highly disputed on it’s usefulness.

The best method is to keep your carbs at a moderate level, no more than 30-40g per meal.