Without a significant other. Applies in both the short term and the long term. After a break-up, one is sugar free until they find another. One can also be deemed sugar free if they are out without their boyfriend/girlfriend for the evening. Though acceptable in use by both genders, a male's usage would generally cause him to be considered gay.
Short term: Girls, let's go out and get our drink on. I am sugar free tonight.
Long term: Gotta find me a man. Can't stay sugar free forever.