Cacao is cocoa that hasn't been roasted properly.
However unlike cocoa, cacao is recently fashionable due to its alleged health benefits of antioxidants and minerals etc. Though it is true that high temperatures do tend to destroy more nutrients than lower temperatures, cocoa still retains much of what cacao does — just at lower levels.
The big difference is that cocoa actually tastes nice, whereas I find cacao unpleasantly sour.
So, my suggestion: replace cacao with nice cocoa, add an extra spoonful to make up for the missing nutrients, then actually enjoy eating it!