Temperance means restraint and moderation, but if you're talking about alcohol, temperance means not just drinking in moderation, it means not having it at all.
The temperance movement appeared in the U.S. in the 19th century, at first urging moderation in drinking but eventually seeking to outlaw alcohol entirely. It managed to get Prohibition enacted in 1919, which did outlaw alcohol, but it was repealed in 1933. Temperance doesn't just have to do with alcohol, it can refer to avoiding any kind of excess: if your new diet requires temperance, you're eating in a balanced, sensible way. Temperance comes from the Latin temperare, "restrain."