To understand why these foods mess with your mind, first think about your tongue.
These little red West African berries make anything sour taste sweet – and it's a remarkably clean, pure sweetness. And for mind-bending parlour tricks, nothing beats miracle fruit. Drink a glass after brushing your teeth with toothpaste, and the normally sweet drink tastes foul instead. Eat one and then drink a glass of water and you might notice that the liquid tastes strangely sweet. It's all because your taste buds respond differently when the environment around them shifts – an effect you can use to go on a little mouth-hacking tour.
What you've just eaten can change the flavour of what you eat next – for better or for worse.