The quick answer to this question is yes, dogs can eat bananas – but only in small quantities.
Bananas are not bad for dogs, per se, and don’t contain any harmful substances. That said, there are still good reasons to be careful.
The problem with bananas is that – like any fruit – they are rich in sugar. Sugar itself is not necessarily a problem for dogs, but it can become a problem when eaten in large amounts.
That because sugar is actually a very harmful substance to dogs and humans. It is addictive, and it also causes damage to the nerves, causes inflammation, and spikes blood sugar.
What you need to remember is that a dog is very small compared to a human. Even a big dog is small compared to a human! Thus, if they eat bananas, they will gain a lot more sugar than if we ate bananas. It’s like you’re giving your dog a whole bunch of bananas every time that you have one!
This can be a problem then as it can spike the blood sugar to a drastic degree. This then in turn causes a surge of insulin, which causes the body to absorb that sugar ready to store or to use. If you keep repeating this process, things get worse still: eventually the body can learn to adapt to the constant spikes in sugar and will eventually stop producing insulin altogether. This then leaves the animal unable to utilize any sugar in future and is what causes diabetes.
Diabetes is a common issue for dogs and can lead to blindness and a host of other issues as the sugar builds up in the blood with nowhere to go. The other things to remember as a dog owner is that dogs aren’t naturally likely to encounter anywhere near as much sugar in their diet as humans. Humans in fact would have survived on a large number of nuts and fruits during their early evolution, whereas dogs who are descended from wolves have a naturally almost carnivorous diet.
Another potential issue with bananas for dogs is that they are very high in fiber. While fiber is good for dogs and humans alike, dogs don’t need as much as humans as their digestion works very differently. Thus, if a dog gets too much fiber, it can actually lead to a host of problems – in particular, it is likely to cause constipation or diarrhea.
Again, for these reasons it is best to give a dog bananas only in small quantities and to keep them as a treat.