Studies have shown that overripe bananas with brown spots are the worst to consume. As bananas ripen, the beneficial starches begin to break down and are converted into sugar.
An overripe medium-sized banana contains 17.4 grams of sugar, while a yellow banana of the same size contains only 14.4 grams of sugar. This means that the sugar from glucose and fructose in the ripe bananas increases by 3 grams.
Sugar levels increase because the starch in the banana, which is a complex carbohydrate, naturally breaks down into simple sugars over time. A yellow banana contains 6.35 grams of starch, which is 0.45 grams for overripe bananas.
Overripe bananas also have less fiber. Ripe bananas have 1.9 grams of fiber while yellow bananas contain 3.1 grams of fiber, which makes yellow bananas great for digestion.
According to a study published in the Journal Diabetic Medicine, diabetics’ blood sugar did not rise much when they consumed unripe bananas compared to when they consumed overripe bananas.
Last but not least, the micronutrient content of overripe bananas also decreases.