According to the current U.S. Food and Drug Administration standard of identity for chocolate, manufacturers must use approved ingredients or the product cannot be labeled as "chocolate."
The chocolate standard now calls for chocolate to be made with cocoa butter, which imparts the rich, smooth, melt-in-your-mouth quality most of us associate with chocolate.
Some members of the chocolate industry have petitioned for a change in the formula to allow substitution of cheaper vegetable fats. If the change goes through, products could be called "chocolate" even if they contained no cocoa butter at all.
Today is the last day for public commentary on the issue at
this FDA link.
More on the issue
here.