A type of tree that grows in West Africa produces a small, red fruit known as a miracle berry. If you eat a miracle berry, everything you eat after it tastes sweet, even sour lemons and vinegar. A chemical in the berry called miraculin binds to your tastebuds, changing the shape of receptors inside. The receptors' changed shape makes everything you eat taste sweet for the next hour. Scientists are working on a sweetener made from miracle berries, so that in the future, foods could contain less sugar.