according to popular belief, for health reasons, pineapple with jackfruit, bananas and eggs, mango with pineapple, pineapples with plantains, and bananas mixed with papayas should never be mixed.  

other combinations to be avoided are pineapples with eggs and bananas with alcohol.

in angra dos reis, it is a popular belief that pineapples or mangos mixed with beans can be harmful, and that eating watermelon or jackfruit at night is bad.  

if a pregnant woman eats bananas she is more likely to have twins.