The YouTuber in this video explores the radioactivity of bananas and other foods. He uses a geiger counter near a stack of bananas and brazil nuts but finds no trace of radiation. He explains that these foods are considered radioactive due to the metal potassium, which is essential to life but also contains a natural radioisotope known as potassium-40. The host conducts experiments to test the radioactivity of concentrated banana peels and brazil nuts and finds that while the radioactivity of bananas is low, the peel contains detectable amounts of potassium. The video also warns viewers about the high selenium content in brazil nuts and cautions against eating mushrooms grown in areas with nuclear fission products. Lastly, the host recommends viewers to subscribe for the next video.