Simple enough: A half-cup serving must contain no more than 3g total fat. Ice creams that don't meet that standard can still be called "reduced-fat" or "light" if they meet those definitions.
Not a nutrition claim but a process that often indicates less fat. Air is added during the churning process—a technique long used to reduce fat and calories—but new technologies reduce the size of fat globules and ice crystals, yielding a creamy consistency. Total fat tends to be in the 3g to 4g zone—somewhere between low-fat and light.
Contains 25% less total fat than a brand's original version. The more fat in the original version, the more in the reduced-fat version. We found a reduced-fat version with 6g total fat and 4g sat fat per half-cup. Another had 5g total fat and 3g sat fat.
How's this for confusing: Light ice creams may contain either 50% less total fat or 33% fewer calories than the brand's original version. For example: One brand's full-fat ice cream contains 180 calories and 9g fat, while the light version has 140 calories and 4.5g fat. Most manufacturers swap some whole milk or low-fat milk for cream to earn the term.
Technically, a fat-free ice milk (it's not an ice cream if it's less than 5% fat) can have up to 0.5g of fat in it—manufacturers can round down. For creamy texture, thickeners and stabilizers (like carrageenan and cellulose gum) are added.