Is it true that bananas are radioactive?
Yes, it's true that bananas are radioactive, however, the amount of radiation that you get from eating a banana is negligible. It's also true that eating too many bananas can kill you, but if you manage to eat enough bananas to get radiation poisoning, you're going to die from something else long before potassium exposure comes into the equation - like, say, the death penalty after murdering the next person to bring a banana within 50 miles of you.



Source https://xkcd.com/radiation/

Bananas are on the left, third from the top. To better communicate the scale, the top legal (i.e. totally negligible) radiation dose for US workers is equivalent to eating 500,000 bananas/year.

There is actually a unit of radiation exposure measurement called the Banana equivalent dose. Suffice to say, there are about a thousand other sources of radiation in your day to day life that you should worry about before how many bananas you eat starts to become a real concern. You can safely eat as many bananas as you please, at least, from a radioactivity standpoint.