Of late, I have been thinking about what I eat in terms of my personal stewardship over my body. If my body is the "temple of God" and has been "bought with a price" I have a responsibility to maintain its sanctity by what goes into and out of it. We are told to "glorify God in [our] body" and that proper treatment and use of our body will lead to its sanctification.
We learn that the "natural man is an enemy to God." Thus, in this life we are to "bridle all [our] passions" and subject our carnal desires. This, in my opinion, is one of the principle purposes of fasting - to learn how to allow our Spirits to gain traction over our bodily desires, to practice the arts of self-mastery so that we can be more in-tune with the Lord's guidance of our lives. I also believe this is a major theme in the Word of Wisdom. The Word of Wisdom provides guidance that can facilitate self-mastery and strengthening of the spiritual. By helping us to bridle some of those passions, we are promised the blessings of wisdom, knowledge, strength, and divine protection. It is for our temporal salvation, "that every one of [us] should know how to possess [our] vessel in sanctification and honor."
Eating is tricky, because so often we do not immediately see the effects of what we do, or we don't tie food directly to how we feel. While we often focus on certain facets of the connection between the physical and spiritual, we often miss that connection when it comes to eating. But the virtues of patience and self-mastery can be so perfectly developed in making decisions about what we eat. We live in a society of self-indulgence, even hedonism at times. We want things, and we want them now. I am reminded of President Uchtdorf's talk on patience. We are becoming so unaccustomed to having to wait for anything or postpone pleasure, and this includes our eating habits. "He that hath no rule over his own spirit is like a city that is broken down, and without walls." But how often are we ceding our rule over our spirit to our temporary desires? Do you know how sweet a strawberry is when you eat no other sugar?
I am not advocating that everybody stop eating sugar - it is simply my personal decision based on my feelings of my stewardship over my body. But, I feel strongly about my need for self-mastery and temperance. I feel that what I eat has an influence on my ability to feel the Spirit and communicate with God. As I practice self-mastery, my spiritual tendencies are refined and I feel I am a better steward over what God has given me. "The same is a perfect man, able also to bridle the whole body."