Eat them cheetah spotted, they don't digest well when not like that.
I would think it depends on the variety of banana, common sense tells me to eat them when they taste best to you. Some varieties are probably ripe when they have black spots all over them and others are probably ripe when they're yellow with no spots, etc. So just eat them when they taste the sweetest and most pleasant to you, but hey, there must be a bunch of banana experts on this site, and I'm not one of them.
So perhaps someone else can elaborate for you...
Just recently I found out plantains are best when completely black, just some spots is unripe. See here http://www.30bananasaday.com/forum/topics/how-does-ripe-fruit-look-...
I tried to go for unripe bananas at first too. But I would put them in the blender and it was much harder to blend than soft, spotty bananas. The smoothies came out way to thick-- almost chewable. They hadn't really been broken down too much. It's the same thing inside your body. You won't get much out of them like that-- they won't digest and it'll be harder for your body to extract the nutrients. I don't like extremely ripe bananas either, but I wait at least for a complete yellow with some brown speckles.
i use to like them unripe as well, after a while i got use to eating them spotty now i cant eat them unripe.
You like unripe bananas? Try eating 15 of them. You won't like them much anymore.
Almost everyone used to like unripe bananas in their pre-811 lives. That is because they would eat 1-2 at a time, max and wouldn't notice the digestive problems. Stomach has a hard time breaking down the complex carbs in unripe bananas. Very taxing.