The difference between cacao and cocoa is Cacao is raw, cocoa is roasted.
Here's some info on it from Wiki Answers at http://wiki.answers.com/Q/What_is_t..._and_cocoa
Theobroma cacao (Cacao Tree) is the tree from which the Cacao bean comes. Cacao beans are found inside the "fruit" of the tree, pods about the size of a football.
Cocoa is what the beans are called once they have been cleaned, roasted and processed.
Cacao is the same bean but still in the raw state, uncooked and unprocessed.
The ORAC value comparison per 100 grams
1) Raw cacao powder 95,500
2) Raw cacao nibs 62,100
3) Roasted cocoa powder 26,000
Raw cacao is comprised of over 300 compounds including: Carbohydrates, protein, fat, fiber, iron, copper, zinc, magnesium, calcium and sulfur.
Cacao once cooked and processed ("Cocoa") Loses much of its nutritional goodness which are destroyed by the heat. Once milk is added the antioxidant levels drop also dramatically. This is what you find in the popular chocolate bars and candies.
Raw foodists will only use and advocate raw cacao for its high nutritional value which gives it the "superfood" status.
In the United States, cacao is often referred to simply as cocoa, which leads to the confusion as to the difference between the two.
Read more: http://wiki.answers.com/Q/What_is_t..._and_cocoa