Diabetics need to be conscious of their total sugar / carb intake. Bread, pasta, rice, fruit, sugar etc - they all increase your blood sugar. Some fruits like mangoes, ripe bananas, watermelon can be quite high in sugar and depending on the amount consumed, can spike your blood sugar. A small piece of mango should be fine, whereas a whole, large ripe mango could increase blood sugar. Other fruits like berries and pears are much lower in sugar. Generally, you want to avoid the high-sugar fruit while also being aware of your total sugar / carb intake. Best way to do this is to monitor your blood sugar levels at home, and get Hb1ac tested every 3 to 6 months. If your blood sugar levels are stable, then some fruit and carbs is fine. If your blood sugar levels are unstable, you might need to cut back on fruit and other carbs, and possibly adjust your diabetes meds (with medical professional help).