Yes, In moderation Diabetic individuals may eat mangoes. It's also in the recommended list of American diabetes association guidelines.
One medium size mango contains 100-135 calories with around 25 grams of carbohydrates and 3 gram of fibre. It's also very rich in minerals, vitamin A and C.
So accordingly you need to make some changes in your diet plan in exchange for mangoes to balance your daily calorie intake. Important to note is that it is rich in fibre which delays absorption of sugar. It has a low glycaemic index of 51.
Fruits like watermelons, pineapple and dried fruits should be better avoided.