Sweet on chocolate? It's what's inside – cocoa powder – that counts

It's a headline sure to make people keep reading: Is chocolate good for you?

Almost everyone wants the answer to be yes, of course. But there isn't a simple response to be swallowed whole. So, like a good bar of chocolate, let's break it into bite-sized pieces.

Chocolate actually starts with the cacao bean, the seed of the fruit of a cacao tree. It contains fiber and natural compounds with antioxidant properties called phytonutrients. Fiber is great for the digestive tract and may lower the risk of heart disease and some cancers, while antioxidants are believed to help the body resist heart disease, cancer and other diseases.

Crushed and roasted, the cacao bean becomes cocoa, the basic building block of chocolate.

The idea of cocoa as a key to health isn't new. The Mayans and Aztecs believed cacao was a gift from the gods, and used it for healing and for rituals. The cacao tree is native to the Americas, but once Europeans heard about it, they caught on fast. The Florentine Codex, written in the 16th century by a Spanish friar describing life in the New World, was just the first of many reports enlightening Europe about cacao's medicinal benefits.

More recently, studies have suggested that cocoa consumption might help with heart health factors such as blood pressure and cholesterol, and can boost artery health, vision and brain function.

So, are you putting down the celery and reaching for a chocolate bar? Not so fast.

"Hopefully, I'm not going to give an answer that's too depressing," said Dr. Deepak L. Bhatt, director of Mount Sinai Fuster Heart Hospital in New York City. "I am a chocolate lover, but I'm not deceiving myself that I'm doing it for anything except giving myself a treat."

The reason is all too clear: To turn bitter cocoa powder into delicious,...