Of all fruits, berries can arguably claim to be the most important for diabetics but here again it is more nuanced than that.
Berries, especially blueberries, strawberries, and raspberries, are ideal when looked upon from the perspective of almost every parameter of significance when it comes to blood sugar control. They have low glycemic index, high amount of fibers compared to their sugar content and significant levels of antioxidants like anthocyanins which have proven benefits in studies as insulint sensitisers. Apart from slowing down glucose absorption, they also serve as feedstock for healthy gut bacteria.
There is one fruit that usually does not get any credit for what it brings to the table. The humble guava is low GI fruit, packed with vitamins including vitamin C and dietary fibers, and emerging studies show that consumption of guava helps to regulate blood sugar. Guavas are consumed regularly by diabetics in regions across the globe where they grow commonly.
A more difficult truth is that for the diabetics, timing, amount and the context play extremely crucial roles here. Having banana alone when you are fasting is fundamentally different experience metabolically than consuming the same banana after having a protein rich and fibrous meal.
Watermelon, banana (especially ripened bananas), pineapples and all varieties of fruit juice are to be approached consistently with care. No hard banishment here – just better moderation due to their effect on blood sugar level.
In conclusion, for diabetics, a moderate dose of berries or guava, eaten with meals or after meals, but not alone or in fruit juice form should suffice for their daily needs.