How has the LDS Word of Wisdom changed since its introduction? In the LDS faith, they follow a law of health called the Word of Wisdom that teaches them to abstain from things like alcohol and tobacco and it encourages them to eat foods like grains, fruits, and vegetables.

How has the Word of Wisdom changed since its introduction compared to what it is today?
The revelation known as the Word of Wisdom is set forth in section 89 of the Doctrine and Covenants.  It speaks of basic dietary and health principles, listing substances that are harmful and should be avoided (mainly addictive drugs) and positive things that should be observed (a healthy diet), and promises blessings of health, strength, knowledge and spiritual deliverance to those who observe its principles.

The only substantial change in doctrine between when the Word of Wisdom was first given and modern times is that it was originally given:


  2 To be sent greeting; not by commandment or constraint, but by
  revelation and the word of wisdom, showing forth the order and will of
  God in the temporal salvation of all saints in the last days—
  
  3 Given for a principle with promise, adapted to the capacity of the
  weak and the weakest of all saints, who are or can be called saints.


whereas today it is considered a commandment to the members of the church.  This change was adopted in a general conference of the church in 1851, almost 20 years after the original revelation was given, under the reasoning that it would have been impractical to ask the general population of the church, many of whom were already accustomed to using substances known to be addictive, to give them up all at once, but that by this time they had had plenty of time to phase out the use of such things.

Today, observance of the Word of Wisdom is necessary before a person investigating the church can be baptized, and continued observance is required for a member to be considered worthy to go to the temple.