Abstemiousness, n.
The quality of being abstemious, temperate, or sparing in the use of food and strong drinks. It expresses a greater degree of abstinence than temperance.
Shades of meaning
Fernald has no entry of its own for abstemiousness; he lists it under abstinence.
Where he writes about it:
Abstinence from food commonly signifies going without; abstemiousness, partaking moderately; abstinence may be for a single occasion, abstemiousness is habitual moderation. — from abstinence