Concerning the Word of Wisdom:
LDS like Catholic believe in authoritative interpretation of scripture. Few Catholics keep the laws of Moses. Some Christians only excuse themselves from a small number of these laws because the New Testament does not deal with the others. Some Christians excuse themselves from virtually every concept of law because of the words of the New Testament.
The Word of Wisdom has been interpreted.
We are to abstain from Coffee and Tea (hot and iced, but not herbal). We are to abstain from alcohol and tobacco (topical and medicinal applications are not forbidden and are utilized by some LDS). When one is asked if the keep the Word of Wisdom, one should respond with the above in mind and their own honest assessment of their compliance. Catholics have much to draw parallels to in that there is much to be considered when contemplating mortal and venial sin as it pertains to confession and the Eucharist.
In addition to this Prophets have counseled with respect to other thing peripheral to the WOW. To my knowledge this has never included chocolate. Some LDS may generally abstain from caffeinated beverages while others do not. These are personal chooses.
In addition to this LDS are not immune from certain fanatics. In the ward of friends of ours there is a couple whose mission seems to be to build a comprehensive health code out of the WOW. This type of pharisaical addition to the prescribed guidance of the general authorities is inappropriate.