I'm just adding this as a side note, since Colin's answer was pretty thorough: If you're trying to prevent yourself from GETTING fat, ice cream is a better option for two reasons:

Bite for (Full Tilt Quality) bite, ice cream is more filling: when you take out the delicious fat, you have more sugar per bite bound to not much but a tiny bit of protein and fat. Sugar is not as satiating, and not just because of the calorie count--calorie for calorie, fat fills you up faster while not making your blood sugar spike the way sugar does.

More critically, FAT isn't what makes us fat. SUGAR is. A slab of meat will very efficiently convert to glycogen and store until we need it as glucose. Sugar, though, only has a portion of it stored as glycogen, and the rest the liver processes and stores as fat (fruit juice is even worse than plain table sugar: high fructose contents=high obesity, hence breast fed babies and milk fed being generally alright while soy fed babies--because they have to add corn syrup solids to formula to make it even partly digest--tend to become obese unless they fail to thrive at all). Sugar's real evil in making us fat is in making us insulin resistant (again, fructose is that real culprit). The higher the fructose proportion of a sweetener--agave is actually worse than HFCS!--the more it will make you insulin resistant, first (which is why it takes a long time to detect) in your MUSCLE tissue... then in all the ways that make us DIAGNOSED as being diabetic. When your muscle tissue is insulin resistant, which happens when sugars, fructose in particular, is consumed regularly, you get fatty stores in your arms, thighs, all those places that are extremely hard to work off the extra... and while fructose doesn't make your blood sugar spike (so it's low on a glycemic index but turns out that was faulty science, whoops), it makes you store fat, which in humans is not as delicious as in ice cream. Because the pancreas only responds to the GLUCOSE, we don't recognize that we're developing diabetes when sitting on our tushes drinking juice. The more sugar is BOUND to fiber (whole fruits!) and even to fat, the better the food IS, the slower it is to be converted to fat, the fuller you feel, and the more time you have to run it off before it's a permanent fixture on your rump.

My reason for mentioning? Gelato, as much as I love a good scoop of it, is trying to demonize ice cream for the fat in it which is actually far more healthy than the higher sugar content in gelato. No matter what you're eating, half the fat doesn't--as they'd love to infect your brain with the idea of--mean you get to consume it twice as much. Stop hating on fat (especially milkfat, which has been shown to LOWER bad cholesterol pffth on them). Next they'll go telling us our salmon should be replaced with tilapia and our olive oil with broth to boil everything in... Enjoy either one, in moderation, but I'd blow a raspberry at the less fat notion. It's called the "SnackWell Phenomena," (phenomena, theory, etc) where quite reliably you end up eating more, more calories and more sugar in particular, because the sugary, low-fat treats don't fill you up; you get hungry faster.