"Would you like a piece of chocolate, darling?" Millie looks up at her grandmother in delight. "Yes, please!" she says, and holds out her hand for the delicious-looking dark square.

But when she pops it in her mouth - "Ugh!" It is the most disgusting thing she has ever tasted: not the milk chocolate she was expecting, but dark chocolate. How horrible!

Few things divide people as much as chocolate. Some people like dark, some like milk - but hardly anyone likes both.

Chocolate is made from the seeds of the cacao tree. Confusingly, these are also known as cocoa beans.

It was originally drunk rather than eaten. Traces of it found in Mexico date from 1900 BC.

Chocolate was unknown in Europe until the 16th Century. It slowly became fashionable, and people began buying it in a solid form.

In the 1850s, a Swiss businessman called Daniel Peter invented milk chocolate by adding milk powder. This was a breakthrough because cocoa beans in their natural state are extremely bitter.

Many bars today have wrappers saying how much cacao they contain. Dark chocolate is defined as anything which is at least 35% cacao.

Some people believe that the higher the percentage, the better the chocolate. But according to one expert, Darren Williams, "100% is only good for cooking."

Scientists say that dark chocolate can be good for you, because it contains antioxidantsSubstances that prevent or delay some types of cell damage. called flavanols which help reduce blood pressureThe beating of our hearts keeps our blood at a certain pressure. This pressure can rise when we are stressed, as the heart beats faster.. And according to Professor Jeffrey Blumberg of Tufts University,¹ "Some research suggests that milk may interfere with the absorption of flavanols."

Other research suggests that some people have a gene which make them keener on caffeineA drug that increases the activity of the brain and nervous system. It is found in many drinks, such as tea, coffee and soft drinks, as well as energy drinks, which have large amounts of caffeine. than others. And, says Professor Marilyn Cornelis,² "When they think of caffeine, they think of a bitter taste, so they also enjoy dark chocolate."

Yes: It tastes much sweeter. Dark chocolate was drunk by the AztecsThe most powerful Central American civilisation in 1492, when Europeans first made sustained contact with the Americans. Their civilisation was destroyed by the Spanish, who enslaved what was left of their people., who were keen on human sacrifice and sometimes mixed it with blood, so it has a dark history as well as appearance.

No: Milk chocolate does not have the same health benefits as dark, because the milk interferes with the flavanols which help your blood pressure. The more bitter chocolate is, the better.

Or... No chocolate is really good for you. It is bad for your teeth and contributes to people becoming overweight. It also melts easily and ends up as a sticky mess which can ruin your clothes.