There are two basic differences that distinguish Italian gelato from regular ice cream — fat and air. Gelato is composed of 90% milk, as opposed to regular ice cream, which contains a 50/50 mixture of milk and cream.
Additionally, while regular ice cream is filled with as much as 60% air, the air content of gelato is only 34%. These differences give gelato a creamier, smoother texture and a richer, fuller flavor than traditional ice cream. Put simply, gelato is the tastier, healthier alternative.