For a product to carry the label of “ice cream” in the US it has to have a minimum 10% fat content. Lower quality ice cream will be around 11 or 12%, while higher quality products will hit 16% and higher.
Gelato is a different thing all together- since the milk-to-cream ratio is much higher, the fat content is significantly lower- anywhere between 3 and 8%. This is particularly important when t comes to taste, as the lower fat content doesn’t saturate your taste buds as much, and the flavors have the chance to emerge stronger.
The difference between the weight of the ingredients and the weight of the final product given a fixed volume, used to measure the amount of air that is trapped in the final product, is about 25%-30% in gelato and usually in excess of 50% in ice cream. The reason of the different air content resides in the churning method and the processing speed.
Ice cream is served frozen, while gelato is not- hence the challenge to lick your way around the cone before it melts. You surely cannot be distracted while enjoying a gelato cone