Honestly poisonous foods

Fugu fish. The tetrodotoxin in the fish gland is poisonous. Every chef in japan who offers this fish to his guests have passed years of training of filleting the fish. It is said that in the past the chefs had to eat the cleaned fish themselves. This dangerous practice was meant to destroy the over confidence in the cook and make sure that they will present the safest food possible. The true craft in filleting fugu fish is to leave just a little poison that will be felt by the eating person, but will not cause any major or permanent damage.  

Eating any kind of living creature. The danger here is that the animal will stick to your throat or accidentally enter your lungs. People in Korea eat live octopus as a proof of bravery. Even though there is a trick to doing that, there are many cases with a fatal end.

Any food with mould on it. Brie cheese and blue cheese are quite famous for their taste, but not many people know that the taste comes from the mould that helps the cheese ferment. You can say that penicillin is created out of the mould, but that is a completely different matter. Here once more, the danger comes from the allergies some people have. It is strange but true that a thin slice of cheese can send someone to the hospital and even kill a person.

Ackee fruit is a preferred dish in some parts of Africa. When eating this fruit at any cost avoid the seeds because they contain the poison hypoglycin. Nausea, fatigue, and can even lead to a lethal end to someone who consume the seeds.

Bonus: strange and dangerous food

Brain. There are many cultures from all over the world that eat entrails including the brain. In many parts of Asia, there are recipes that include monkey brain. It is not exactly poisonous food, but it can cause Variant Creutzfeldt-Jakob disease. The disease is similar to Mad Cow disease. Fortunately, the spreading on domesticated animals is nonexisting in most parts of the world. Monkeys, on the other hand, are not domestic animals and therefore may be carriers. It is best to avoid this exotic dish even if you are a great adventurer.