There are three categories of disobedience to God–actions, words and thouights. If we can acquire thought control we can avoid all three forms of disobedience.
The Mormon practice of fasting is to be done in wisdom. Its purposes are to subdue the body and feed the poor. Those taking medication can still accomplish both.
Whether or not a person would be censured by the Lord for killing an animal would depend more on the attitude of the person doing the hunting than on the act itself.