Several medical studies have shown correlations between low-glycemic index fruits and vegetables and decreased incidence of diabetes. Not just this, but low glycemic index fruits also improve control in the treatment of diabetes.
Glycemic index (GI) refers to the “incremental area under the blood glucose curve (AUC) after the consumption of 50 grams digestible carbohydrates from a test food divided by the AUC after eating a similar amount of a control food, generally from glucose or white bread”. In other words: the food’s ability to raise blood sugar levels two hours after consumption of carbohydrate-rich food. A low-glycemic index (<55) means that the carbohydrates in those foods are absorbed slowly, which can be helpful for the body to better manage post-meal changes. Foods with a higher glycemic index (>70) raise the blood sugar levels more quickly. After years of research, the glycemic index is now identified as a reliable classification of food items according to their glycemic effect after a meal. The glycemic index of food items that contain mostly fat and protein was not calculated, since this kind of food items do not have a lot of carbohydrates, and therefore, do not affect the blood sugar levels in the body. 
Low-Glycemic Index & Diabetes Management
In diabetes type 1, the body does not produce insulin or is unable to use it. People with diabetes type 2 have a lack of insulin or cannot use it properly. In diabetes type 1 as well as in diabetes type 2, a carbohydrate-rich diet could be harmful regarding glycemic control, which may play a role in the development of coronary artery disease and other macrovascular and microvascular complications (such as diabetic neuropathy). Moreover, a low-glycemic index diet can help prevent or manage diabetes type 2 in obese and overweight people. Examples of low-GI carbohydrate-containing foods are legumes, starchy vegetables, cereals, and most fruits. These types of food are also named functional foods because of their beneficial effects on the health and well-being of individuals. 
Low-Glycemic Index Fruits
Fruits are not only healthy because of the vitamins they contain, but also because of the low-glycemic index that they have. Furthermore, they can be easily incorporated into a healthy diet. Low glycemic index fruits for diabetes include pears, prunes, peaches, oranges, apricots, dates, apple, strawberries, & more. Let us take a look at 10 such low GI fruits below: 
Pears are not only delicious, but they come with a low Glycemic Index as well. Although low in vitamin C, they are a reliable source of dietary fiber and potassium. There are different variations of pears. Pears canned in reduced-sugar syrup reaches the lowest GI-score, but also raw pears (GI: 33), dried pears (GI: 43), and pear halves canned in natural juice (GI: 43) are good to go.
Prunes are dried plums, rich in dietary fiber and vitamin K. Prunes provide several favorable health benefits. Moreover, they belong to the list of fruits with the lowest Glycemic Index. But, to be on the safe side, do not eat too many of these; as they are dried and have more carbohydrates. Instead, fresh plums are a good alternative, with a GI of 39.
Peaches are an excellent choice for people with diabetes, both peaches canned in natural juice (GI: 30), as dried peaches (GI: 35). Although in small amounts, peaches contain lots of different vitamins.
This popular citrus fruit is a great source of vitamin C and other nutrients. There are several variations, like the blood orange and navel orange. Also, Marmalade made of oranges without added sugars has a low-GI of (27).
An average apricot contains only 48 calories and is a moderate source of vitamins A and C. With a GI between 30 and 32, the dried ones are also a good choice. 
This typical Middle Eastern exotic fruit is a good source of several essential nutrients, like potassium, magnesium, and vitamin B6. The great variations in dates and the way they were packed causes the difference in Glycemic Index.
Apples have a low Glycemic Index and are a good source of dietary fiber. They only provide small amounts of essential nutrients but are easy to eat as a healthy snack.
Strawberries boost your vitamin C and contain a large amount of manganese and other dietary fiber. The dried variant of strawberries has the same GI-score.
As a mutant of the peach, the nectarine is a good source of potassium and magnesium. 100 grams of nectarine only contains 36 calories.
Similar to oranges, the mandarin contains a lot of vitamin C. They are also rich in dietary fiber, vitamin A, and vitamins B1 and B6.