Green bananas are firmer than yellow bananas. Their texture has sometimes been described as waxy. Green bananas are higher in starches. As bananas ripen and turn yellow, the starches transform into sugars. Green bananas may provide some additional nutrients and benefits that yellow bananas do not. They're rich in resistant starch and pectin, which are filling, improve digestive health and help lower blood sugar levels. However, some people find that green bananas have a bitter taste and bad texture.