1) Asceticism feature 2) Key to dieting 3) Personal discipline 4) What a dieter practices 
Self-denial (also called self-abnegation and self-sacrifice) refers to altruistic abstinence - the willingness to forgo personal pleasures or undergo personal trials in the pursuit of the increased good of another. Various religions and cultures take differing views of self-denial, some considering it a positive trait and others considering it a n...
• (n.) The denial of one`s self; forbearing to gratify one`s own desires; self-sacrifice.
Self`-de·ni'al noun The denial of one's self; forbearing to gratify one's own desires; self- sacrifice. 
[n] - the act of denying yourself
self-discipline noun the act of denying yourself; controlling your impulses