Abstemiousness is the habit or quality of being careful not to have too much, especially around food and drink, and often around wine. It names the pattern, not a single evening: “her abstemiousness,” not “tonight’s abstemiousness” in ordinary talk. You will almost only see it in formal or bookish English; nobody at a night market asks for extra of it with their noodles. As with the adjective, the tidy picture is “refuses everything,” but the older, stricter use is “takes little.” A person can show abstemiousness and still eat — just not much, and without fuss. It is a character word more than a medical one; doctors today are more likely to say “cutting down” or “not drinking.” The -ness ending does not change the meaning; it only turns the description into a noun you can point at.

飲食有節制（指這種習慣，書面）