The health benefits are just one blessing given to us by living the Word of Wisdom, but I think that more than a code of health, it is a simply a test of obedience.
The principle is: if you are obedient then you will be blessed with a promise of health.
But what happens if health in this world isn't given?
What exactly is the promise?
Section 89 of the Doctrine and Covenants tells us what the promise is:
18 And all saints who remember to keep and do these sayings, walking in obedience to the commandments, shall receive health in their navel and marrow to their bones;
The Blessing of Health
Health in their navel and marrow to their bones is more than just a physical blessing. This reference in itself is one of life, not merely physical life but Eternal life. The navel is another word for "center point" and is the reminder of the lifeline that we have as a "child of God" to the Father, this life line is Christ. Christ is also the marrow or "rich and nutritious food" on which we rely; He is the "innermost or essential part" that we need to live.
Just like the marrow is the food or blood for the bone, the blood of Christ provides us with the living matter we need to be resurrected. This is the application of the Atonement in our lives. The health we enjoy now temporally is a added blessing for living the Word of Wisdom, but the eternal health we will be given is guaranteed because of the application of the Atonement.
Wisdom and Knowledge
Where do we gain wisdom and knowledge other than from the spirit and the Temple itself. One of the requirements to enter the Temple is obedience to the Word of Wisdom. Simply stated, we are blessed with the opportunity to attend the sessions in the Temple where we gain wisdom and knowledge that will effect us eternally.
Stamina and Energy
Isn't it interesting how the world has even tried to counterfeit this blessing with the energy drinks and stimulants of today. Pure energy comes from one source and that is God.
With reference to the "destroying angel" the Lord is leading us back to the Passover during the time of Moses. It was here inside the house where the blood of the lamb was spread over the doorposts that the Children of Israel were saved.
Today just as in those days, it is because of receiving the blessings of being inside the house that we will also be saved. Entering the "House of Israel" is done by covenant. Those covenants are available because of the priesthood blessings and are part of being in the House of the Lord.
The word of wisdom is an Eternal principle and is one that promises Eternal blessings!